Patent Publication Number: US-2015059580-A1

Title: Forensic air and surface sampler technology (fasst) collector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 61/870,544 which was filed on Aug. 27, 2013 and which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     The invention described herein was partially supported by government funding from the United States of America. The invention described herein may be manufactured and used by or for the government of the United States of America for government purposes and the government has certain rights in the invention. (U.S. Government Client is United States Department of Homeland Security—Contract: HSHQDC-10-C-00143). 
    
    
     BACKGROUND OF THE INVENTION 
     Biocrime investigation is dependent on the ability to reliably collect and preserve biological materials that may be present on surfaces associated with a crime scene. Recovery of sufficient quantities of biological evidence that are comingled with other evidence components such as hairs, fibers and dust confounds the problem of collecting and preserving the integrity and viability of the biological component from the evidence sample matrix. The ability to separate small biological particles of interest from larger associated materials while preserving viability would enhance sample collection, improve biological sample processing, and increase the ability to expand in culture the bioagent used to perpetuate the crime. 
     The 3M™ Forensics Vacuum  10  is the technology commonly employed for collecting forensic biological samples. This device is shown in  FIG. 1  and includes a vacuum unit  12  and a filter cartridge  14 . The biological sample is collected in the filter cartridge and then undergoes an extraction process for forensic analysis. The filter is prone to breakthrough failures resulting in sample loss. The filter typically experiences breakthrough due to the amount of material collected, which includes dust and other non-biological materials. In cases where filter integrity is maintained, extraction of the biological sample is inefficient and makes forensic trace analysis difficult as there is no segregation of small biological particles in the collected sample. 
     The current 3M™ Forensics Vacuum technology commonly employed for collecting forensic samples from dry surfaces suffers from filter collapse which results in loss of vital evidence material. Sample processing of the 3M™ filter is complicated by a difficult to open filter housing and manipulations required to remove the filter typically results in sample loss and contamination of biosafety cabinets used for sample processing. These issues increase the time and expense of sample processing and jeopardize the integrity of the forensic sample, and justify the need for better sampling technology. 
     The discrete recovery of individual components of interest from a complex forensic sample is also complicated by the overabundance of extraneous materials and further complicated by the potential presence of biological threat agents indicative of a biocrime collection. The ability to de-convolute a complex sample by segregating sample components at the time of sample collection, based on size, charge or other physical or chemical characteristics, enhances the recovery of discrete evidentiary components and provides more rapid sample processing methods. 
     SUMMARY OF THE INVENTION 
     Development Overview 
     Applicant developed a dry surface particle collector as a modular attachment to the commercial-off-the-shelf (COTS) 3M™ Forensics Vacuum System in response to filter breakthrough failures typical of the current 3M™ collection system. Four different collector embodiments have been developed to date. 
     The Forensic Air and Surface Sampler Technology (FASST) Mk I collector is based on electrostatic precipitator (ESP) technology developed by Applicant for similar biological particle sampling missions. The design includes an inertial particle separation technique to deliver the specific particle size range of interest to the ESP for collection onto a coated surface. The collector preferentially targets particles within the 1 to 25 micron size range, the typical size range for biological threat agent materials, and sends such smaller particles through the ESP tube portion of the MK I collector. The ESP tube employs a high voltage (HV) power supply to provide approximately 10,000 volts DC to a wire electrode suspended within a grounded aluminum collection table. This configuration generates a corona discharge to ionize the sample air stream and create free electrons. The smaller particles entering the ESP tube collector encounter the ionization field which causes them to efficiently precipitate onto the collection tube walls. Applicant developed the coating methods and extraction protocols to efficiently remove viable biological agents and nucleic acids from the collector&#39;s coated surface. 
     FASST Mk I prototypes were laboratory tested using  B. anthracis  Sterne spores and Vaccinia virus to evaluate target compatibility and stability with ESP technology. Pre-validation test results indicated the integration of the ESP into the vacuum collection system did not adversely affect target collection or interfere with the collection system. 
     The FASST Mk II collector was also developed based upon the test results relating to the FASST Mk I collector. The FASST Mk II collector is similar to the Mk I except that the inertial separator has been removed from the particle stream inside the collector tube. The aerosol dispersion and dust size distribution test conducted on the Mk I collector highlighted the fact that the inertial separator was not necessary and that eliminating the inertial separator on the Mk II collector actually reduces sample loss and increases collection efficiency. In addition, the Mk II design no longer requires a user to remove the ESP electrode wire from the collection tube prior to sample recovery. Once the sample tube is removed from the FASST system, end caps are simply placed onto each end to contain the sample during subsequent recovery steps. 
     The FASST Mk II collector also provides greater collection of biological particles and improves on the device&#39;s ease of use and robustness over the FASST MK I design. During Phase H, the FASST Mk II underwent additional test and evaluations to collect  B. anthracis  Sterne spores and Vaccinia virus from a variety of solid and carpeted surfaces. A long term stability study was also conducted on the ESP tube coating to optimize the tube storage and validate coating efficacy under a variety of environmental conditions. 
     The FASST Mk III collector was also developed based upon the test results associated with both the Mk I and the Mk II collectors. The Mk III collector is a portable hand-held collector which includes an electronics housing, a collection tube module having an intake nozzle and a filter adapter, a bottom sliding cover, and a 12 volt battery which is installed within the handle portion of the collector housing. The two main components of the FASST Mk III collector are a single-use collection tube assembly and a reusable battery housed within a main housing which includes the electronics, the DC-voltage power supply, and redundant safety mechanisms for high-voltage protection. In all other respects, the FASST Mk III collector functions similar to the Mk I and Mk II collectors and likewise includes an ESP collection tube assembly as previously explained. 
     The FASST MK III collector was further improved by modifying some components to make it easier to manufacture and by further adding an automatic altitude adjustment feature and an electrostatic charge dissipation feature to the collector. The present system relies on corona discharge to ionize the system and charge and collect the incoming particulates. The onset of the corona discharge is a function of many environmental variables such as temperature, humidity, air pressure as well as geometric variables such as the radius of the electrode wire. The improved MK III system automatically adjusts the electrode voltage based upon atmospheric pressure measurements from an onboard pressure sensor. This feature is an improvement over the previous systems since corona onset voltage can vary by several thousand volts depending on whether the system is used at sea level or in mountainous regions and can be added to the previous systems.) 
     The improved MK III system also uses a static discharge element or conductor associated with the collector tube to dissipate any excess charge which may build up on the collection tube. A bundle of fine tipped electrical conductors are electrically connected to the collection tube at one end and the other end of the conductors are positioned at the center of the rear end of the collector tube adjacent to the filter adapter. This arrangement aids in the dissipation of any excess charge on the collection tube back into the airstream entering the vacuum. 
     The primary benefits of the FASST collectors are their ability to compartmentalize small particles within the size range of biological organisms for rapid recovery in a pre-coated collection vessel designed to stabilize collected organisms and promote rapid live culture recovery. By compartmentalizing the biological particles of interest, the FASST devices eliminate the sample loss problem encountered in current devices (3M filter for example). In situ extraction from the FASST collection vessels also minimizes sample loss and eliminate the potential for cross contamination between samples, a requirement for evidence that could be used in a legal proceeding. Laboratory stability testing demonstrated two-week stability for recovery of nucleic acid signature and spores from ESP tubes which supports operational field requirements for post-collection sample stability. The FASST collection system provides end users with a unique collection system which greatly diminishes sample processing time particularly for viable organisms. The ability to expand the collection of culture biological agents from a crime scene provides the opportunity to gather detailed microbiological analysis including biochemical analysis, serotyping, virulence determination, antibiotic susceptibility in additional to sequencing and genotyping data, critical data points to determine source attribution. 
     There are virtually limitless scenarios that can be envisioned for introducing pathogens into the environment. A wide array of potential surfaces can be exposed to these bioweapons. The variety of methods for disseminating bioweapons and the many surfaces and matrices that the weapons may encounter present significant challenges for effective environmental sampling for bioweapons. Nevertheless, pathogens such as bacteria remaining in the environment subsequent to a biological attack provide a potentially rich source of evidence for use in criminal investigations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
         FIG. 1  is a perspective view of the prior art COTS 3M™ Trace Evidence Vacuum and Dry Filter. 
         FIG. 2  is a photograph of the FASST Mk I Prototype (with 3M filter and Vacuum attached). 
         FIG. 3  is a schematic of the particle dynamics inside the MK I Forensics Collector Assembly. 
         FIG. 4  is a graph showing aerosol dispersion test results for the ESP and 3M Filter. 
         FIG. 5  is a photograph showing typical debris greater than 2000 μm sieved from: a) Office Floor and b) Honda Civic. 
         FIG. 6  is a graph showing typical office vacuum collection: a) % Volume vs. Particle Diameter b) % Particle Count vs. Particle Dia. 
         FIG. 7  is a graph showing typical vehicle collection (Honda Civic): a) % Volume vs. Particle Diameter b) % Particle Count vs. Particle Dia. 
         FIG. 8  is an exploded view of the FASST Mk II components. 
         FIG. 9  is a side elevational view of the FASST MK II Collector (Assembled). 
         FIG. 10  is a perspective view of the 3M™ vacuum hose/choke assembly. 
         FIG. 11  is a perspective view of a fully assembled FASST Mk II Collection System. 
         FIG. 12  are perspective views of a sample collection tube fitted with sealing end caps. 
         FIG. 13  is an exploded perspective view of the FASST MK II collector components evaluated in capacity testing. 
         FIG. 14  is a top plan view of the dry surfaces used for sample collection—a) Rough tile surface, b) low pile carpet surface. 
         FIG. 15  is a Real-Time PCR Amplification of Bacillus anthracis recovered from FASST ESP Collection Tubes Standards 1e5 (Green), 1e4 (Red), 1e3 (Orange), 1e2 (Gray), Samples (Blue), PCR No Template Controls (Black). 
         FIG. 16  is a Real-Time PCR Amplification of Vaccinia recovered from FASST ESP Collection Tubes Standards 1e5 (Green), 1e4 (Red), 1e3 (Orange), 1e2 (Gray), Sample (Blue), PCR No Template Controls (Black). 
         FIG. 17  is a chart showing the sample distribution of 5 grams of Ultra-Fine Arizona Road Dust collected by the FASST Mk II Sampler. 
         FIG. 18  is a chart showing the sample distribution of 5 grams of Standard Reference Material collected by the FASST Mk II Sampler. 
         FIG. 19  is a chart showing the sample distribution of 5 grams of office debris collected by the FASST Mk II Sampler, demonstrating the size segregation capabilities. 
         FIG. 20  is a chart showing the sample distribution of 5 grams of Auto Debris collected by the FASST Mk II sampler, demonstrating the size segregation capabilities. 
         FIG. 21  is a chart showing Real-Time PCR Amplification of  B. anthracis  Spores collected from Dry Surfaces Standards 1e5 (Green), 1e4 (Red), 1e3 (Orange), 1e2 (Gray), Samples (Blue), PCR No Template Controls (Black). 
         FIG. 22  is a Real-Time PCR Amplification Curve Vaccinia collected from Dry Surfaces Standards 1e5 (Green), 1e4 (Red), 1e3 (Orange), 1e2 (Gray), Sample (Blue), PCR No Template Controls (Black). 
         FIG. 23  is a chart showing  B. anthracis  and Vaccinia Real-Time PCR results for the stability study. 
         FIG. 24  is a chart showing  B. anthracis  plate count results for the stability study. 
         FIG. 25  is a chart showing Pre-Validation FASST Mk II Collections Real-Time PCR results for rough tile surface. 
         FIG. 26  is a chart showing Pre-Validation FASST Mk II Collections Real-Time PCR results for carpet surface. 
         FIG. 27  is a chart showing Pre-validation COTS 3M™ Collections Real-Time PCR results for carpet and rough tile surfaces. Samples 4 and 8 (hashed bars) were processed for live culture prior to nucleic acid extraction. 
         FIG. 28  is a chart showing Pre-Validation Live Culture Recovery from rough tile and carpet surfaces. Green bars represent amount of viable target recovered from ESP rinsate tubes using the FASST Mk II Collector. Purple bars represent amount of viable target recovered from standard 3M filters using the COTS 3M Forensic Vacuum System. 
         FIG. 29  is an exploded perspective view of the FASST MK III collector components. 
         FIG. 30  is a cross-sectional view of the FASST MK III collector tube assembly. 
         FIG. 31  is an exploded perspective view of the electronics housing/center case assembly. 
         FIG. 32A  is a side elevational view of the high voltage supply assembly. 
         FIG. 32B  is a side elevational view of the high voltage supply assembly with certain parts removed from view for clarity purposes. 
         FIG. 32C  is a top plan form view of the high voltage supply assembly. 
         FIG. 32D  is a top plan view of the high voltage supply assembly with certain parts removed from view for clarity purposes. 
         FIG. 33  is a perspective view of the intake nozzle associated with the collection tube assembly of the FASST MK III collector. 
         FIG. 34  is a perspective view of the filter adapter associated with the collection tube assembly of the FASST MK III collector. 
         FIG. 35  is a perspective view of the bottom slide cover associated with the FASST MK III collector. 
         FIG. 36  is an exploded perspective view of the handle assembly associated with the FASST MK III collector. 
         FIG. 37  is a perspective view of the FASST MK III collection tube module shown in both its collection configuration and its containment configuration. 
         FIG. 38  is an exploded perspective view of the FASST Mark III Components. 
         FIG. 39  is an exploded perspective view of FASST MK III Collection Tube Assembly Procedure. 
         FIG. 40  is an exploded perspective view of the FASST MK III electronics housing and collection tube. 
         FIG. 41  is a bottom perspective view of the electronics housing. 
         FIG. 42  is a perspective view of electronics housing and collection tube assembly. 
         FIG. 43  is an exploded view of the FASST Mark III collector with the bottom sliding cover removed. 
         FIG. 44  is a perspective view of the FASST MK III collector with the bottom slide cover in its assembled condition. 
         FIG. 45  is a perspective view of a fully assembled FASST MK III collector. 
         FIG. 46  is an exploded perspective view of the FASST MK III collector showing the 12 volt battery removed. 
         FIG. 47  is a perspective view of the FASST MK III collector with the 12 Volt Battery in its assembly condition. 
         FIG. 48  is a perspective view of the 3M™ vacuum hose/choke assembly associated with the FASST MK III collector. 
         FIG. 49  is a perspective view of the 3M™ Dry Filter connected to the vacuum hose/choke assembly. 
         FIG. 50  is a perspective view of a fully assembled FASST MK III Collector. 
         FIG. 51  is a cross-sectional view of the improved FASST MK III collection tube module showing the electrostatic discharge conductor associated therewith. 
         FIG. 52  is an enlarged end view of the improved FASST MK III collection tube module showing the installation of electrostatic discharge conductor in greater detail. 
         FIG. 53  is a perspective view of the improved FASST MK III collection tube module showing the static discharger within the collection tube. 
         FIG. 54  is a cutaway view of the improved FASST MK III collection tube module showing the configuration of the static discharger within the collection tube. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description of the present invention references the accompanying drawing figures that illustrate specific embodiments in which the invention can be practiced. The several embodiments disclosed herein are intended to describe aspects of the present invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the spirit and scope of the present invention. The present description is not to be taken in a limiting sense and shall not limit the scope of equivalents to which the appended claims are entitled. 
     FASST Mk I Overview 
     Applicant initially designed and tested a prototype of the Forensic Air and Surface Sampler Technology (FASST) system  16  for biological evaluation as illustrated in  FIGS. 2 and 3  during Phase I of the program. The device  16  includes an outer tube  20  and an inner electrostatic precipitator (ESP) collection tube  22  and uses an inertial separator  18  coupled to the ESP collection tube  22 . The inertial separator  18  was designed to remove large particles from the airflow stream entering the ESP collection tube  22  and shunt them to the outer tube  20  and to the standard 3M™ dry filter for collection. The smaller particles entering the collection tube  20  encounter an ionization field generated by the electrode wire suspended within the ESP tube  22  that causes them to precipitate on the walls  23  of the ESP tube  22 .  FIG. 3  is a schematic showing the particle flow inside the Mk I collector. The Mk I system has excessive particle loss in the outer bypass tube (the flow path through which the large material (large particulates, hair, fibers, etc.) is diverted by the inertial separator) as illustrated in  FIG. 3 . Since this outer tube is not generally cleaned to extract samples, particles collected on the outer tube may be considered lost sample. 
     FASST Mk I Baseline Testing 
     Applicant initiated a series of tests to better understand the true collection efficiency of the ESP and determine the baseline performance of the FASST Mk I system. By understanding the efficiency of the current design, future design modifications could be implemented to improve the overall collection efficiency of the device. 
     Aerosol Dispersion Testing 
     This testing used ammonium fluorescein disseminated at multiple particle sizes to trace depositions within the FASST Mk 1 device. Test operators used a Vibrating Orifice Aerosol Generator (VOAG, Model No. 3450, TSI, Inc., St. Paul, Minn.), to introduce monodisperse particles of ammonium fluorescein into the flow system. The VOAG generates droplets in approximately 2.5-cfm airflow. The ammonium fluorescein droplets dry to solid particles while traveling through a charge neutralizer and drying tube before injection into the test system. The test operators positioned the VOAG&#39;s charge neutralizer so that the exiting ammonium fluorescein aerosol entered into the flow system through a PVC tee-connector. The required make-up air entered the flow system through HEPA filters (3M GVP-440) positioned on the ends of the PVC tee-connector at the inlet of the flow tube. 
     Test operators positioned the FASST MK I device within the flow system, downstream of the inlet tee-connector. They also placed an EPM 2000 glass fiber filter (#1882866 Whatman, Ltd., Maidstone, England) downstream from the FASST device. This exhaust filter captured any ammonium fluorescein particles that passed through the MKI prototype system. The operators monitored the air stream flow rate using a roots meter and blower located at the end of the flow system. All dispersion tests were performed at the flow rate of 400 L/min using 1.1, 1.7, 5.5, 10.4 and 16.4 μm ammonium fluorescein particles. 
     To determine the collection efficiency, operators compared the amount of ammonium fluorescein captured in the FASST Mk 1 system to the total mass of ammonium fluorescein captured in the flow system. At the conclusion of each test, the test operators disassembled each component of the FASST Mk I system, exhaust tube and exhaust filter and then individually rinsed each component using 0.1 N ammonium hydroxide (NH 4 OH). An aliquot of the thoroughly mixed rinsate was then acquired for fluorometric analysis. Scientists performed analysis of ammonium fluorescein rinsates using Applicant&#39;s PerSeptive biosystems fluorimeter, a Cytofluor multi-well plate reader, Series 4000 (Applied Biosystems, Foster City, Calif.). 
     Results of the aerosol dispersion test are illustrated in  FIG. 4 . It should be noted that this data was collected from a small sample of tests (&lt;2 replicates). These results show that a significant percentage of particles are collected on non-recoverable surfaces. For example, the 1.1 micron data indicates that approximately 50% of the material is collected on surfaces other than the ESP collection tube and the 3M™ filter. These losses are reduced to 20% as the particle size increases to 10 microns. Consequently, the ESP portion of the sample contained less 1-25 micron material than originally intended. This was a direct result of using the inertial separator  18 , which allows &gt;40% of the 1-25 micron material to flow completely around the ESP portion and into the 3M™ dry filter. 
     Dust Size Distribution Tests 
     The objective of the dust size distribution studies was to determine an approximate sample mass and particle distribution for vacuum collection in a typical field collection. Samples were collected from several office floors and seventeen employee vehicles from the Applicant&#39;s Florida facility. The tested vehicles included 2 and 4-door cars, large and small trucks, SUV&#39;s, and a mini-van. It was found that a typical car yielded approximately 15 g of particulate with approximately 5 g of that material coming from the trunk area. These masses do not include bulk material such as grass, leaves, or similar materials greater than 2000 micron in size as this material was sieved from the sample prior to particle, size analysis. See,  FIG. 5 . 
     Particle size analysis using the Beckman Coulter Particle Analyzer ( FIGS. 6 and 7 ) shows the heterogeneous nature of these real-word samples. While both the office and vehicle samples indicate the collection of some massive particulate (&gt;20 micron) based on the particle size diameter (by % volume), a majority of the collected particulate are, in fact, less than 10 micron (by % number). This data indicates that the inertial separator  18  included in the FASST Mk I system is not a critical feature since most of the collected particulate will be less than 10 micron and comparable to the size of unclumped target biological material. 
     Baseline Testing Results 
     The aerosol dispersion and dust size distribution tests highlighted the fact that the inertial separator  18  used in the Mk I system is not necessary and that eliminating it on the Mk II system reduces sample loss and increases collection efficiency. The ESP within the FASST Mk II still preferentially collects small particulate matter (&lt;25 micron) due to the fact that larger particles have too much inertia to be captured and retained efficiently on the walls of the ESP collection zone. Thus, the Mk II design still segregates the sample based on particle size. Additionally, omission of the inertial separator reduces the complexity of the FASST Mk II device and simplifies the sample extraction process. 
     FASST Mk II 
     Design Goals 
     Operational testing was conducted using several dispersion methods to simulate realistic conditions of agent release and to characterize the FASST Mk I performance under a variety of test conditions. Throughout these tests, as well as the baseline testing during Phase II, three key areas of improvement for the Mk II were identified: 1) Performance Enhancement—changes intended to increase sampling and extraction efficiency, 2) User Operability—changes intended to improve the device&#39;s ease of use, and 3) Design Robustness—changes intended to improve the robustness of the prototype system. These three areas were addressed during the Phase II design process and the results are described in the following sections. 
     Mk II System Design Overview 
     Similar to the FASST Mk I system, the core technology in the FASST Mk II is an electrostatic precipitator (ESP) that employs a high-voltage (HV) power supply to provide approximately 10,000 volts DC to a wire electrode similar to wire electrode  24  suspended within a grounded aluminum collection tube similar to ESP tube  22 . This configuration generates a corona discharge to ionize the sample air stream and create free electrons. Smaller (1 to 20 μm) particles entering the ESP tube encounter the ionization field, causing them to efficiently precipitate onto the collection tube walls. Due to their inertia, larger particles pass through the ionization field and are captured by a secondary dry filter located downstream of the ESP. The 3M™ vacuum is the primary air mover for the FASST Mk II. 
     The MK II system&#39;s two main components are a single-use collection tube assembly  26  and a reusable AC-powered main housing  28  which contains the electronics, the DC high-voltage power supply, and redundant safety mechanisms for high-voltage protection as illustrated in  FIG. 8 . Removing the collection tube assembly for analysis takes less than 20 seconds and is a tool-free process. 
     FASST Mk II Operation 
     The FASST Mk II system has a simple high voltage ON/OFF switch  30  to enable high voltage and three LEDs  32  indicating operational status as best shown in  FIG. 9 , green LED  32 A indicating that power is supplied to the unit, yellow LED  32 B indicating that the interlock has been activated, and red LED  32 C indicating that the High Voltage switch is on and supplied to the unit. A microprocessor controls the operation of the hardware, including the high voltage power supply, status LEDs  32  and safety mechanisms. It requires 120VAC (standard wall outlet voltage/current) to operate and includes a power connection  33  for plugging into a standard wall outlet power source. The unit powers on as soon as it is plugged into standard wall power, so the High Voltage switch  30  should be in the OFF position to begin. As soon as the Mk II system is plugged in and supplied with standard 120VAC, all three status LED&#39;s  32  will blink simultaneously for approximately 5 seconds. Once the blinking stops, the green and yellow LED&#39;s  32 A and  32 B will remain on steady. This indicates that the Mk II system is ready for high voltage to be enabled. Once the High Voltage switch  30  is moved to the ON position, the Ted High Voltage LED  32 C will be on steady. This indicates that high voltage is being supplied to the FASST Mk II&#39;s electrostatic precipitator and the unit is functioning properly. 
     The FASST Mk II system has several safety mechanisms that protect the unit and operator from damage and injury due to high voltage exposure. The FASST Mk II system will not enable high voltage unless it is fully assembled. There are two safety interlocks that will prevent high voltage from turning on if the full collection tube assembly and bottom sliding door  34  ( FIG. 8 ) are not fully installed. Additionally, if either of these two components are removed from the unit during operation or become dislodged or not properly installed or positioned within the housing, high voltage will immediately be disabled. The safety interlocks are Hall Effect (magnetic) sensors that signal the micro-processor when an ESP tube is installed and the safety cover closed. This safety mechanism is indicated by the yellow Interlock LED  32 B. Under normal conditions, the yellow LED  32 B is on steady. It will blink in different patterns if any component is missing from the unit. The switches are hidden from the user&#39;s sight within the electronics enclosure to reduce the likelihood of a user circumventing the safety interlocks. A detailed description of the safety interlocks is set forth below with reference to the MK III system. It is recognized that any other safety/sensing mechanism may likewise be used in this particular application such as micro switches and optical sensors. 
     The electronics in the Mk II receive feedback from the internal high voltage power supply. Excessive current draw, under voltage, and excessive power supply temperature are all monitored and can be signs of a possible electrical short or other malfunction. The high voltage power supply will be shut down if any of these scenarios are detected. This will be indicated by a blinking red High Voltage LED  32 C in regards to an excessive current draw or under voltage, and a blinking green LED  32 A for an overheating scenario. Table 1 shows all possible LED status scenarios for the FASST Mk II system. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 LED Stats Indicator Table 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 PWR 
                   
                   
                   
                   
                   
                   
               
               
                 PLUG 
                 TUBE INSTALLED 
                 DOOR INSTALLED 
                 GREEN LED 
                 YELLOW LED 
                 RED LED 
                 HV STATUS 
               
               
                   
               
               
                 OFF 
                 NA 
                 NA 
                 OFF 
                 OFF 
                 OFF 
                 OFF 
               
               
                 ON 
                 NO 
                 NO 
                 ON 
                 OFF 
                 OFF 
                 OFF 
               
               
                 ON 
                 YES 
                 NO 
                 ON 
                 BLINK SLOW 
                 OFF 
                 OFF 
               
               
                 ON 
                 NO 
                 YES 
                 ON 
                 BLINK FAST 
                 OFF 
                 OFF 
               
               
                 ON 
                 YES 
                 YES 
                 ON 
                 ON 
                 BLINK SLOW (1/SEC.) 
                 HV CUR BAD 
               
               
                 ON 
                 YES 
                 YES 
                 ON 
                 ON 
                 BLINK FAST (10/SEC.) 
                 HV VOLT BAD 
               
               
                 ON 
                 YES 
                 YES 
                 BLINK FAST 
                 ON 
                 ON 
                 OVER TEMP 
               
               
                 ON 
                 YES 
                 YES 
                 ON 
                 ON 
                 ON 
                 HV GOOD 
               
               
                 ON 
                 YES 
                 YES 
                 ON 
                 ON 
                 OFF 
                 HV OFF-SWITCH 
               
               
                   
               
            
           
         
       
     
     The FASST Mk II system should be unplugged during assembly and disassembly and when the device is not in use. All FASST Mk II components need to be completely dry before assembly and use with residual moisture in the system can increase the hazard of electrical arcing. Applicant has designed the FASST MK II system with the ability to access the inside of the electronics housing for diagnosis and repair. This is an operation that can only be performed by designated personnel, and at no time should the electronics housing be opened by unauthorized personnel. 
     FASST Mk II Assembly and Collection Tube Removal 
     The FASST Mk II assembly and collection tube module removal procedures are simple, tool free processes. A disassembled Mk II unit is illustrated in  FIG. 8 . To begin assembly, the intake nozzle  36  and filter adapter  38  are attached to the collection tube module  26 . This assembly is clipped into the electronics housing. Finally, the bottom sliding cover  34  is attached and secured in place with a simple magnetic closure  35 A and  35 B. The fully assembled Mk II system is illustrated in  FIG. 9 . The collection tube module  26  is removed by reversing this procedure. 
     FASST Mk II Collection System Assembly 
     The FASST Mk II system is designed to work in conjunction with the 3M™ Trace Evidence Vacuum  12  and Dry Filter  14  which are seen in  FIG. 1 . A choke  40  is used to reduce the flow of the 3M™ vacuum hose  12  ( FIG. 10 ) down to 400 L/min, which is the optimal air flow for the Mk II. The fully assembled FASST Mk II Collection System is illustrated in  FIG. 11 . 
     Testing and Evaluation of the FASST Mk II 
     The Mk II system design incorporates several improvements over the Mk I design to simplify the recovery of collected material. The Mk II design no longer requires a user to remove the ESP electrode wire from the collection tube prior to sample recovery. Once the sample tube is removed from the FASST system, end caps such as caps  42  and  44  are simply placed onto each end to contain the sample during subsequent recovery steps as illustrated in FIG.  12 . This method not only eliminates the cumbersome step of removing the electrode wire, it also allows for recovery of sample material that may have been collected on the electrode wire. 
     A series of tests were designed and executed to evaluate the FASST MK II design. These tests were designed to further examine the FASST device and understand the environment and the properties of the particles the device will encounter in a field scenario. Challenging the FASST Mk II device in varying ways facilitates understanding of how the design changes improved collection as well as determine how the device will perform in scenarios an end-user might encounter. The series of tests are detailed below. 
     Initial Evaluation 
     The Initial Evaluation Study was performed to become familiar with the new prototype to ensure modifications were compatible with the existing extraction Standard Operating Procedure (SOP) for sample extraction (SOP 110724.002: Extraction of  B. anthracis  and Vaccinia from the Forensic Air and Surface Sampler Technology (FASST) System for use in Live Culture and PCR Analysis) which was developed during Phase I. 
     Capacity and Particle Size Testing 
     Applicant performed capacity testing of the FASST Mk II prototype to evaluate performance of the sampler when challenged with increasing levels of dry dust and debris. This testing included sample types that might be encountered in real world sampling scenarios. For these studies, the test protocol required that un-seeded dry dust be distributed onto a tile surface and then collected by the FASST Mk II prototype. Increasing levels of dust ranging from 0.5 grams to 10 grams per surface collection were tested to evaluate the collection capacity of the sample collection tube and to evaluate performance of the system for its intended use. The downstream 3M™ filter  14  was replaced with the Fibertect® matrix with customized DHS filter holder to prevent potential sample loss in the event of 3M™ filter rupture. Applicant weighed the component parts of the prototype before and after collection to determine how the collected sample is distributed in the component parts of the FASST Mk II prototype.  FIG. 13  provides a picture of the FASST system components that Applicant weighed before and after sample collection:
         Collection nozzle  36     FASST sample collection tube  26     Filter holder adapter  38     Downstream Fibertect® filter and filter housing unit (not pictured)—The customized Matrix filter holder and Fibertect® filter were used as the downstream filter unit to avoid sample loss due to potential failure of the standard 3M™ filter.       

     Applicant evaluated four types of dry dust in the study to include samples spanning a variety of particle sizes in addition to real world samples:
         Ultra-Fine Arizona Road Dust (UF-ARD): (1-10 μm, Powder Technologies Inc., A1 Ultrafine Test Dust, ISO 12103-1)   Standardized Reference Material (SRM): (0-40 μm produced by MRIGlobal for the DHS BIAD II program)—consisting of dust and particulates collected from HVAC systems across the US.   Office vacuum dust: (un-sieved)—collected from MRIGlobal offices   Automobile dust: (pre-sieved of particles &gt;2 mm)—collected from MRIGlobal staff automobiles.       

     Applicant bulk-collected the representative real world samples used in this study (office dust and automobile dust) from an office setting and automobile interiors to represent typical collection events anticipated in the field. Applicant vacuum collected particulates from Applicant&#39;s office floors using a standard upright vacuum from office areas with varying levels of foot traffic, to be representative of standard office environments. The office debris used for the FASST capacity testing was not sieved of large particles and is representative of true real world sample. Automobile samples were collected from cars using a standard Shop Vac. The automobile dust and representative office debris were analyzed on a Beckman Coulter Particle Analyzer to generate statistics on typical particle size number and percent volume distributions. 
     The real world samples, office and automobile debris, discussed previously were evaluated in this study and show the heterogeneous nature typical of natural samples. The office sample contained a wide variety of particle sizes greater than 20 μm while the vehicle sample contained particles with an average size of 500 μm. In both samples, the majority of particles had diameters smaller than 10 μm which is similar in size to that of unclumped biological material. These masses do not include bulk material such as grass, leaves, or similar materials greater than 2000 μm in size which were sieved from the samples for particle size analysis. 
     Seeded Dry Surface Collections 
     Based on the results of the capacity testing, the Standard Reference Material (SRM) was determined to be the best candidate background material to suspend lyophilized  B. anthracis  spores and Vaccinia for distribution onto test surfaces. Dry surface collections studies were conducted to evaluate the collection and recovery capability of the FASST Mk II collector. Eightly grams of bulk seeded SRM was prepared using lyophilized  B. anthracis  spores and Vaccinia virus which were mixed into pre-sterilized SRM to be used for surface collection studies. Seeded SRM was prepared as a dilution series using the SRM background as a dry diluent. Spores and virus were mixed into the SRM by thorough mixing with a spatula and hand agitation to homogenize the mixture. Mixtures used were of one-thousand fold, ten thousand fold and one hundred thousand fold dilution series of the starting lyophilized materials. Target levels of  B. anthracis  and Vacinnia in the final preparation of 2.0 grams of seeded SRM were enumerated by PCR. Plate count data was also used to estimate the levels of  B. anthracis . Lyophilized Vaccinia when mixed into the SRM was found to be not viable using the established Cytopathic Effect (CPE) method. Loss of Vaccinia viability may be due to abrasive mixing of the lyophilized particles into the SRM. The estimated levels of target in 2.0 grams of seeded SRM used for subsequent dry surface collections was 1.6 6  CFU/gram of  B. anthracis  spores and 2e 7  PFU/gram of Vacinnia particles. 
     Stability Study 
     Using the established extraction method and detection methods, a stability study was conducted to evaluate the post-collection target stability in the ESP tube. Representative 2.0 gram samples of the SRM seeded with lyophilized  B. anthracis  Sterne spores and Vaccinia virus were collected from a tile surface with the FASST Mk II collector. A total of ten samples were prepared to establish duplicate collected samples for testing at each time point. ESP collection tube and 3M™ filter samples were stored at room temperature and processed in duplicate at the following time points: Day zero, 3 days, 7 days, 10 days and 13 days. Samples were tested by PCR and plated for live culture recovery of  B. anthracis  Sterne at each time point. 
     Pre-Validation 
     The FASST Mk II forensic collection system was challenged to simulate operational surface collection from rough tile and carpet surfaces in a pre-validation study. Sixteen replicate surface collections with the FASST Mk II system were conducted to demonstrate repeatability and reliability of performance. FASST Mk II system performance was compared to the standard 3M™ collection system during pre-validation testing. Dry surface collection of seeded SRM was performed using a single target level. A 2.0 gram sample of seeded SRM was administered to a rough surface ceramic tile and low pile carpet surface ( FIG. 14 ). 
     Each 2.0 gram sample collected contained an estimated 3e 6  CFUs of spores and 4e 7  PFU virus particles. Each sample was vacuum collected with the FASST Mk II collector for a total of one minute using a grid pattern across the surface. Four replicate samples for each surface type were collected by the standard 3M™ system for comparison to the FASST Mk II forensic collector and processed using existing methods for recovery of  B. anthracis  and Vaccinia nucleic acids and viable  B. anthracis  spores. Two representative samples from the standard 3M™ collections were processed for live culture using a protocol provided by DHS. Briefly, the 3M™ filter was recovered from the filter housing and pre-wet with 10-mLs of phosphate buffered saline (PBS) and vortexed gently for 30 seconds. A 100 μL aliquot of rinsate was plated neat and serial diluted and plated on solid agar media. The rinsed filter was then processed for nucleic acid recovery according to standard methods. 
     Testing and Evaluation of the FASST Mk II Collector Initial Evaluation 
     Three replicate tubes were spiked with 1e3 CFU/PFU  B. anthracis  Sterne spores and Vaccinia virus then extracted with 6-mL of PBS in accordance with the SOP. Real time PCR analysis was conducted on resulting nucleic acids for Vaccinia and  B. anthracis  gene targets. Extract was plated on TSA/SBA solid agar media for live culture recovery of  B. anthracis . PCR data is compiled in Table 2 and Table 3 below as well as in  FIGS. 15 and 16 . Control samples were used and are identified in the Tables as Sample Type as follows:
         (1) Controls—either no bio sample material (target) included in the sample or test sample added;   (2) actual tube samples; and   (3) IE BA standard samples with a known quantity of standard bio material.       

     The Ct column refers to the cycle threshold and indicates the actual or mean number of cycles necessary to read the sample or replicate the DNA with confidence. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Real-Time PCR Results for  Bacillus anthracis  Recovered from 
               
               
                 FASST ESP Collection Tubes 
               
            
           
           
               
               
               
               
            
               
                 SAMPLE 
                   
                   
                   
               
               
                 TYPE 
                 SAMPLE 
                 Ct 
                 MEAN Ct 
               
               
                   
               
               
                 Controls 
                 Master mix No template control 
                 N/A 
                 NA 
               
               
                   
                 Master mix No template control 
                 N/A 
               
               
                   
                 Sample add No template control 
                 N/A 
                 NA 
               
               
                   
                 Sample add No template control 
                 N/A 
               
               
                 Test #1 
                 Tube 1 
                 NA 
                 NA 
               
               
                 Samples 
                 Tube 1 
                 NA 
               
               
                   
                 Tube 2 
                 39.0 
                 39.3 
               
               
                   
                 Tube 2 
                 39.6 
               
               
                   
                 Tube 3 
                 39.5 
                 38.4 
               
               
                   
                 Tube 3 
                 37.3 
               
               
                 Standards 
                 1E5 BA standard 
                 25.8 
                 25.8 
               
               
                   
                 1E5 BA standard 
                 25.8 
               
               
                   
                 1E4 BA standard 
                 29.1 
                 29.2 
               
               
                   
                 1E4 BA standard 
                 29.3 
               
               
                   
                 1E3 BA standard 
                 32.6 
                 32.7 
               
               
                   
                 1E3 BA standard 
                 32.7 
               
               
                   
                 1E2 BA standard 
                 36.1 
                 36.2 
               
               
                   
                 1E2 BA standard 
                 36.2 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Real-Time PCR Results for Vaccinia Recovered from 
               
               
                 FASST ESP Collection Tubes 
               
            
           
           
               
               
               
               
            
               
                 SAMPLE TYPE 
                 SAMPLE 
                 Ct 
                 AVERAGE Ct 
               
               
                   
               
               
                 Controls 
                 Master mix No template 
                 N/A 
                 NA 
               
               
                   
                 control 
               
               
                   
                 Master mix No template 
                 N/A 
               
               
                   
                 control 
               
               
                   
                 Sample add No template 
                 N/A 
                 NA 
               
               
                   
                 control 
               
               
                   
                 Sample add No template 
                 N/A 
               
               
                   
                 control 
               
               
                 Test #1 Samples 
                 Tube 1 
                 33.9 
                 34.3 
               
               
                   
                 Tube 1 
                 34.7 
               
               
                   
                 Tube 2 
                 35.3 
                 35.6 
               
               
                   
                 Tube 2 
                 35.8 
               
               
                   
                 Tube 3 
                 36.1 
                 36.5 
               
               
                   
                 Tube 3 
                 36.8 
               
               
                 Standards 
                 1E5 Vac standard 
                 24.5 
                 24.9 
               
               
                   
                 1E5 Vac standard 
                 25.2 
               
               
                   
                 1E4 Vac standard 
                 28.8 
                 28.9 
               
               
                   
                 1E4 Vac standard 
                 28.9 
               
               
                   
                 1E3 Vac standard 
                 32.9 
                 32.9 
               
               
                   
                 1E3 Vac standard 
                 32.9 
               
               
                   
                 1E2 Vac standard 
                 35.8 
                 35.6 
               
               
                   
                 1E2 Vac standard 
                 35.3 
               
               
                   
               
            
           
         
       
     
     Recovery of the Vaccinia target is consistent with historical data for similar spike level from Phase I test and evaluation studies (data not shown). The  B. anthracis  recovery however was lower than expected and upon review an error in calculation of  B. anthracis  spike stock was discovered. The true spike level used in the experiment was 8e 2  CFU which is below the reliable limit of detection for the protocol which resulted in late Cts and failed detection from one tube replicate. Although the seed level was lower than intended,  B. anthracis  colonies were recovered on live culture plates from all three tubes with average colony counts of 58 colonies from neat extract. Overall, the redesigned prototype assembly is compatible with the extraction protocol developed in Phase I with no need for further development of the protocol. 
     Capacity and Particle Size Testing 
     Capacity testing of the FASST Mk II collector was conducted by testing increasing levels of unseeded dry dust and debris of four different sample types to determine the sample distribution within the components of the collector. Component parts which included: the collection nozzle  36 , the FASST sample collection tube  26 , the filter holder adapter  38  and the downstream Fibertect® filter were weighed before and after collection. Sample recovery from the FASST Mk II sample collection tube for each type of debris tested is compiled in Table 4 below. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Capacity Testing and Sample Recovery from the 
               
               
                 FASST Mk II Sample Collection Tube 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Pre-weight 
                 Post-weight 
                   
                 % 
               
               
                   
                 (g) 
                 (g) 
                 Δ (g) 
                 Recovered 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 UF ARD 
                   
                   
                   
                   
               
               
                 TestMass 
               
               
                 0.5 grams 
                 61.4412 
                 61.4785 
                 0.0373 
                 7.46 
               
               
                 1.0 grams 
                 62.1805 
                 62.8357 
                 0.6552 
                 65.52 
               
               
                 2.0 grams 
                 61.0560 
                 62.5701 
                 1.5141 
                 75.71 
               
               
                 3.0 grams 
                 61.8122 
                 63.7151 
                 1.9029 
                 63.43 
               
               
                 4.0 grams 
                 61.9119 
                 64.3548 
                 2.4429 
                 61.07 
               
               
                 5.0 grams 
                 62.1027 
                 64.5728 
                 2.4701 
                 49.40 
               
               
                 10.0 grams  
                 62.2526 
                 66.4700 
                 4.2174 
                 42.17 
               
               
                 SRM Test Mass 
               
               
                 0.5 grams 
                 62.2221 
                 62.6902 
                 0.4681 
                 93.62 
               
               
                 1.0 grams 
                 62.3717 
                 63.2544 
                 0.8827 
                 88.27 
               
               
                 2.0 grams 
                 62.0566 
                 63.7769 
                 1.7203 
                 86.01 
               
               
                 3.0 grams 
                 60.7582 
                 63.4269 
                 2.6687 
                 88.96 
               
               
                 4.0 grams 
                 62.2906 
                 65.7606 
                 3.4700 
                 86.75 
               
               
                 5.0 grams 
                 62.4910 
                 67.0600 
                 4.5690 
                 91.38 
               
               
                 10.0 grams  
                 61.8779 
                 71.2658 
                 9.3879 
                 93.88 
               
               
                 Office Debris 
               
               
                 0.5 grams 
                 62.0973 
                 62.2051 
                 0.1078 
                 21.56 
               
               
                 1.0 grams 
                 61.7620 
                 61.9117 
                 0.1497 
                 14.97 
               
               
                 2.0 grams 
                 62.4702 
                 62.6190 
                 0.1488 
                 7.44 
               
               
                 3.0 grams 
                 68.8260 
                 70.0461 
                 1.2201 
                 40.67 
               
               
                 4.0 grams 
                 62.2146 
                 63.8155 
                 1.6009 
                 40.02 
               
               
                 5.0 grams 
                 69.1386 
                 69.2959 
                 0.1573 
                 3.15 
               
               
                 10.0 grams  
                 62.5678 
                 68.4988 
                 5.9310 
                 59.31 
               
               
                 Auto Debris 
               
               
                 0.5 grams 
                 61.4048 
                 61.6116 
                 0.2068 
                 41.36 
               
               
                 1.0 grams 
                 61.3027 
                 61.3573 
                 0.0546 
                 5.46 
               
               
                 2.0 grams 
                 60.9508 
                 61.5403 
                 0.5895 
                 29.48 
               
               
                 3.0 grams 
                 68.9020 
                 68.9854 
                 0.0834 
                 2.78 
               
               
                 4.0 grams 
                 61.4075 
                 61.3586 
                 −0.0489 
                 −1.22 
               
               
                 5.0 grams 
                 68.7719 
                 69.6303 
                 0.8584 
                 17.17 
               
               
                 10.0 grams  
                 61.8541 
                 65.9458 
                 4.0917 
                 40.92 
               
               
                   
               
            
           
         
       
     
     The FASST Mk II collector had the highest collection efficiency with the collection of Standard Reference Material (SRM) which has a particle size range of 0-40 μm. Over 80 percent of the total SRM sample was collected in the sample collection tube and over 98 percent of the total sample was recovered within the sampler component parts. The collector worked exceptionally well over the entire range of sample SRM sizes from 0.5 g-10 g. The most challenging sample type for the ESP was the auto debris. In this test the sample collection tube caught an average of 19% of the total sample mass, with four of the seven tests having lower than 19% of the total sample captured in the sample collection tube. This behavior is expected, given that auto debris is primarily made up of larger particles (average size=500 μm) that the ESP has been specifically designed to not capture. Collection summaries and representative data from the 5.0 gram collections of each debris type are illustrated in  FIGS. 17-20 . 
     Ultra-Fine Arizona Road Dust: (0-10 μm Particle Size) 
     Capacity testing of the FASST Mk II collector using the Ultra-Fine Arizona Road Dust (UF-ARD) demonstrated that the device reached its maximum efficiency at 2.0 grams in regards to the percentage of the total sample captured in the sample collection tube. The collection tests at 0.5 grams and 1.0 gram revealed increases in percent of dust collected in the sample tube, while these same tests showed decreases in the percent collected on the Fibertect® filter behind the ESP; however after reaching the peak efficiency, the percent of the total dust sample collected in the sample tube dropped as the percent of the total dust sample collected on the Fibertect® filter increased. Nevertheless it should be noted that the total mass collected in the sample tube rose with the increase in sample size during each subsequent test. Applicant observed no extreme limitations with regards to the maximum amount of sample that could be collected in the collector tube. In six of the seven collection points taken, at least 49% of the total sample was collected in the sample collection tube. Caking action of the UF-ARD was observed to occur on the collection nozzle with an average of 14% of the sample collected on this component part. The sample collection tube and the Fibertect® filter together accounted for more than 80 percent of the total sample collected for each test run with the UF-ARD. Representative data from the 5.0 gram collection of UF-ARD is illustrated in  FIG. 17 . 
     Standard Reference Material: (0-40 μm Particle Size) 
     The capacity tests carried out with the ESP using the Standard Reference Material (SRM) demonstrated highly efficient ESP capture. In each test, the FASST MK II prototype recovered over 98 percent of the sample dispersed onto the vacuuming surface. Over 80 percent of that material was collected in the sample collection tube consistently with each increasing sample load. In contrast to the test carried out with the UF-ARD, there was not an observed sample size that demonstrated maximum capacity of the sample collection tube. Instead all collections were consistent and very similar, with the collection tube capturing most of the sample and the filter behind the ESP catching the majority of the rest. Applicant noted no significant sample loss in the collection nozzle or the filter holder adapter, nor did we find any limitations in regards to the amount of sample the ESP tube could collect; as the sample mass increased, so did the sample captured in the collection tube. Representative data from the 5 gram collection of SRM is illustrated in  FIG. 18 . 
     Office Debris: (Un-Sieved) 
     The two previous capacity tests demonstrated that the FASST Mk II collector is highly efficient at collecting when the sample is within the target particle size range. The office and vehicle debris capacity tests demonstrate the size segregation capabilities of the FASST Mk II collector. As discussed earlier, the office debris is a heterogeneous mixture with the percentage of particles in regards to count fewer than 10 μm and the percentage of particles in regards to volume over 500 um. On average, the FASST Mk II system collected approximately 92.3% of the total office-debris sample distributed onto the vacuuming surface during the capacity testing. However, in six out of the seven tests, less than 50% of the total collected sample was retained in the sample collection tube. The rest was caught in large part by the Fibertect® filter at the back end of the ESP device. This is a direct result of the ESP letting the large particles pass on to the filter as it is designed to do. There was not a defined trend in amount of sample collected in the sample collection tube which was inconsistent and ranged from less than 3% for the 5.0 gram sample to 59% for the 10.0 gram sample. At the 3.0 gram test sample loose debris was observed suspended in the filter holder adapter which was lost during disassembly indicating the capacity of the sampler was reached. This observation was consistent as the sample size increased. This is due to the fact that the office debris was made up of much larger particles outside the targeted particle size range of the ESP and is significantly more heterogeneous than SRM or UF-ARD Large particulates were caught in the grates of the collection nozzle which prevented these particulates from entering the device but was uncontained during and after sample collection. A design modification to the collection nozzle may overcome this observed limitation and will be addressed in Phase 3 of the program. Representative data from the 5 gram collection of office debris is illustrated in  FIG. 19 . The collection percentage of the sampler tube demonstrates the size segregation capabilities of the FASST Mk II system. 
     Automobile Debris: (&lt;200 mm Particle Size) 
     The automobile debris tests were similar to the office debris tests in that a smaller mass percentage of the dispersed sample was collected in the sample tube by the ESP, indicating size segregation. On average, 19% of the sample was collected in the sample tube and 74% was captured by the Fibertect® filter. The majority of the remaining sample was captured by the collection nozzle followed by the filter holder adapter. Similar to the office debris samples there was no distinguishing trend in collection with regards to the amount of material collected in the sample collection tube, due to the highly heterogeneous nature of the debris. The percentage of total mass that was captured in each test seemed to vary by at least an order of magnitude in each subsequent test. Loose debris and loss of sample was also noted as the collector appeared to reach collection capacity with the heterogeneous auto debris sample type at 2.0 grams. Representative data from the 5 gram collection of auto debris is illustrated in  FIG. 20 . 
     Fibertect® Filter Vs. 3M™ Filter Evaluation 
     In each suite of testing with the FASST Mk II collector, Applicant conducted a replicate sample of the 2.0 gram collection of each dust type using the original 3M™ filter to compare against the Fibertect® filter in its DHS custom housing as the downstream filter. The 2.0 gram sample was selected as a moderate sample load to compare the two filter types. The objective was to determine if the substitution of the Fibertect® filter for the 3M™ filter had any impact on sample collection efficiency of the FASST device. Data are compiled in Table 4 below. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 FASST Mk II Sample Recovery with 3M ™ vs Fibertect Filter 
               
               
                 For Collection of 2.0 gram Sample of Various Debris 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Recovered 
                 Recovered 
                   
                   
                 Higher 
               
               
                 Debris type and 
                 mass (g) with 
                 mass (g) with 
                   
                 Higher 
                 recovery 
               
               
                 component 
                 3M filter 
                 Fibertect filter 
                 % Difference 
                 recovery 3M 
                 Fibertect 
               
               
                   
               
            
           
           
               
            
               
                 UF-ARD 
               
            
           
           
               
               
               
               
               
               
            
               
                 Sample collection tube 
                 1.009 
                 1.514 
                 33.4 
                   
                 ✓ 
               
               
                 Collection Nozzle 
                 0.144 
                 0.224 
                 35.7 
                   
                 ✓ 
               
               
                 Filter 
                 0.675 
                 0.195 
                 71.0 
                 ✓ 
               
               
                 Filter holder adapter 
                 0.012 
                 0.063 
                 80.5 
                   
                 ✓ 
               
            
           
           
               
            
               
                 SRM 
               
            
           
           
               
               
               
               
               
               
            
               
                 Sample collection tube 
                 1.634 
                 1.720 
                 5.0 
                   
                 ✓ 
               
               
                 Collection Nozzle 
                 0.002 
                 0.125 
                 98.7 
                   
                 ✓ 
               
               
                 Filter 
                 0.359 
                 0.143 
                 60.2 
                 ✓ 
               
               
                 Filter holder adapter 
                 0.004 
                 0.010 
                 65.0 
                   
                 ✓ 
               
            
           
           
               
            
               
                 Office Debris 
               
            
           
           
               
               
               
               
               
               
            
               
                 Sample collection tube 
                 0.172 
                 0.149 
                 13.5 
                 ✓ 
                   
               
               
                 Collection Nozzle 
                 0.000 
                 0.004 
                 88.9 
                   
                 ✓ 
               
               
                 Filter 
                 1.689 
                 1.653 
                 2.2 
                 ✓ 
               
               
                 Filter holder adapter 
                 0.005 
                 0.010 
                 45.3 
                   
                 ✓ 
               
            
           
           
               
            
               
                 Auto Debris 
               
            
           
           
               
               
               
               
               
               
            
               
                 Sample collection tube 
                 0.014 
                 0.590 
                 97.6 
                   
                 ✓ 
               
               
                 Collection Nozzle 
                 0.012 
                 0.024 
                 51.0 
                   
                 ✓ 
               
               
                 Filter 
                 1.972 
                 0.984 
                 50.1 
                 ✓ 
               
               
                 Filter holder adapter 
                 0.002 
                 0.020 
                 92.0 
                   
                 ✓ 
               
               
                   
               
            
           
         
       
     
     During this limited testing, Applicant noted that there was a relationship between the filter type used as the downstream filter and the efficiency of the sample collection in the sample collection tube. In the cases of the UF-ARD, SRM, and auto debris, the FASST Mk II ESP collector performed better when the Fibertect® filter was downstream instead of the 3M™ filter. There was 33% more UF-ARD, 5% more SRM and 98% more Auto debris collected in the filter collection tube when the Fibertect® filter was downstream of the ESP. In the case of the office debris collection there was 13% more debris recovered in the sample collection tube when the 3M™ filter was used. A more detailed study with increased replicate testing will provide additional data to evaluate the downstream filter component and its potential impact on the collection efficiency of the FASST collector. 
     Seeded Dry Surface Collections 
     The seeded dry surface collections evaluated the FASST Mk II system and the recovery of biological targets suspended in the SRM background for collection from solid surfaces. Stocks of SRM seeded with lyophilized  B. anthracis  Sterne spores and Vaccinia were prepared as described previously and a 2.0 gram sample was vacuum collected with the FASST Mk II collector. Collected samples were processed for target recovery from the FASST ESP tube (rinsate) and the downstream 3M™ filter and analyzed by real-time PCR and live culture recovery of  B. anthracis  Sterne. Overall the spore target was readily recovered from the ESP collection tube and the 3M™ filters. Minor variability was noted in target recovery from ESP collection tubes. The standard deviation between replicate collections of  B. anthracis  spores was 2.2 between ESP collection tubes and 0.1 from 3M™ filters. This variability is expected given the sample-to-sample variation of lyophylized target suspended in sampled aliquots of seeded dust suspended on the solid surface. Results are summarized in Table 5 below and  FIG. 21 . 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Real-Time PCR Results for 
               
               
                   Bacillus anthracis  Spores Collected from Dry Surfaces 
               
            
           
           
               
               
               
               
               
            
               
                 SAMPLE 
                   
                   
                 MEAN 
                   
               
               
                 TYPE 
                 SAMPLE 
                 Ct 
                 Ct 
                 STDEV 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Controls 
                 Master mix no template control 
                 N/A 
                 NA 
                   
               
               
                   
                 Master mix no template control 
                 N/A 
               
               
                   
                 Sample add no template control 
                 N/A 
                 NA 
               
               
                   
                 Sample add no template control 
                 N/A 
               
               
                 Samples 
                 RINSATE-1 
                 26.9 
                 26.5 
                 2.2 
               
               
                   
                 RINSATE-1 
                 26.2 
               
               
                   
                 RINSATE-2 
                 30.8 
                 30.9 
               
               
                   
                 RINSATE-2 
                 31.0 
               
               
                   
                 RINSATE-3 
                 28.0 
                 28.0 
               
               
                   
                 RINSATE-3 
                 27.9 
               
               
                   
                 3M-1 
                 27.5 
                 27.4 
                 0.11 
               
               
                   
                 3M-1 
                 27.4 
               
               
                   
                 3M-2 
                 27.3 
                 27.3 
               
               
                   
                 3M-2 
                 27.3 
               
               
                   
                 3M-3 
                 27.4 
                 27.5 
               
               
                   
                 3M-3 
                 27.7 
               
               
                 Standards 
                 1E5 BA standard 
                 23.1 
                 22.8 
               
               
                   
                 1E5 BA standard 
                 22.4 
               
               
                   
                 1E4 BA standard 
                 26.1 
                 26.1 
               
               
                   
                 1E4 BA standard 
                 26.1 
               
               
                   
                 1E3 BA standard 
                 29.6 
                 29.6 
               
               
                   
                 1E3 BA standard 
                 29.7 
               
               
                   
                 1E2 BA standard 
                 32.5 
                 32.3 
               
               
                   
                 1E2 BA standard 
                 32.0 
               
               
                   
               
            
           
         
       
     
     More variability was noted in the Vaccinia collections from dry surfaces particularly on the 3M™ filter. The standard deviation between replicate collections of Vaccinia in the ESP collection tube was 1.6. Higher standard deviation (3.9) was noted for recovery of Vaccinia from the 3M™ filters. Contributing factors to the higher variability of Vaccinia may include the smaller particle size and potential uneven target suspension in the SRM background. The results are detailed in the Table 6 below and  FIG. 22 . 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Real-Time PCR Results for Vaccinia Collected from Dry Surfaces 
               
            
           
           
               
               
               
               
               
            
               
                 SAMPLE 
                   
                   
                 MEAN 
                   
               
               
                 TYPE 
                 SAMPLE 
                 Ct 
                 Ct 
                 STDEV 
               
               
                   
               
               
                 Controls 
                 Master mix no template control 
                 N/A 
                 NA 
                   
               
               
                   
                 Master mix no template control 
                 N/A 
               
               
                   
                 Sample add no template control 
                 N/A 
                 NA 
               
               
                   
                 Sample add no template control 
                 N/A 
               
               
                 Samples 
                 RINSATE-1 
                 24.0 
                 24.1 
                 1.6 
               
               
                   
                 RINSATE-1 
                 24.1 
               
               
                   
                 RINSATE-2 
                 28.7 
                 27.0 
               
               
                   
                 RINSATE-2 
                 25.4 
               
               
                   
                 RINSATE-3 
                 26.4 
                 26.8 
               
               
                   
                 RINSATE-3 
                 27.2 
               
               
                   
                 3M-1 
                 25.3 
                 25.4 
                 4.0 
               
               
                   
                 3M-1 
                 25.5 
               
               
                   
                 3M-2 
                 25.5 
                 25.6 
               
               
                   
                 3M-2 
                 25.7 
               
               
                   
                 3M-3 
                 21.9 
                 18.6 
               
               
                   
                 3M-3 
                 15.3 
               
               
                 Standards 
                 1E5 Vac standard 
                 24.6 
                 24.8 
               
               
                   
                 1E5 Vac standard 
                 24.9 
               
               
                   
                 1E4 Vac standard 
                 29.6 
                 29.5 
               
               
                   
                 1E4 Vac standard 
                 29.5 
               
               
                   
                 1E3 Vac standard 
                 34.7 
                 34.6 
               
               
                   
                 1E3 Vac standard 
                 34.4 
               
               
                   
                 1E2 Vac standard 
                 45.5 
                 41.7 
               
               
                   
                 1E2 Vac standard 
                 38.0 
               
               
                   
               
            
           
         
       
     
     Stability Study 
     Laboratory stability testing demonstrated two-week stability for recovery of nucleic acid signature from 3M™ filters and ESP collection tubes and viable spores from ESP collection tubes which supports operational field requirements for post-collection sample stability.  B. anthracis  Sterne colonies were recovered from ESP collection tubes out to 13 days. Full target detection by PCR was demonstrated for both  B. anthracis  Sterne and Vaccinia up to 13 days when stored at room temperature. Overall target recovery for both  B. anthracis  and Vaccinia targets was similar from Day zero through Day 13. Although a decline in overall viability was noted, over 1e 5  CFU/mL of  B. anthracis  was readily recovered from ESP collection tubes after 13 days of storage. Results are summarized in the Table 7 below and  FIGS. 23 and 24 . 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                   B. anthracis  and Vaccinia Real-Time PCR Results for the Stability Study 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 ESP 
                   
               
               
                   
                   
                 rinsate 
               
               
                   
                   
                 Mean 
               
               
                   
                   
                 Ct 
                 3M Mean 
               
               
                   
                 Time Point 
                 (n = 4) 
                 Ct (n = 4) 
               
               
                   
                   
               
            
           
           
               
            
               
                   B. anthracis  Recovery 
               
            
           
           
               
               
               
               
            
               
                   
                 Day 0 
                 27.73 
                 31.15 
               
               
                   
                 Day 3 
                 29.86 
                 30.31 
               
               
                   
                 Day 7 
                 29.31 
                 30.69 
               
               
                   
                 Day 10 
                 28.12 
                 31.29 
               
               
                   
                 Day 13 
                 28.20 
                 29.86 
               
               
                   
                 STDEV 
                 0.90 
                 0.59 
               
               
                   
                 (Day 0-Day 13) 
               
            
           
           
               
            
               
                 Vaccinia Recovery 
               
            
           
           
               
               
               
               
            
               
                   
                 Day 0 
                 26.25 
                 25.24 
               
               
                   
                 Day 3 
                 27.33 
                 25.09 
               
               
                   
                 Day 7 
                 26.00 
                 26.23 
               
               
                   
                 Day 10 
                 26.23 
                 25.32 
               
               
                   
                 Day 13 
                 28.10 
                 24.97 
               
               
                   
                 STDEV 
                 0.90 
                 0.50 
               
               
                   
                 (Day 0-Day 13) 
               
               
                   
                   
               
            
           
         
       
     
     Pre-Validation 
     The pre-validation study resulted in PCR detection from all replicate samples collected from rough tile and carpet surfaces.  B. anthracis  and Vaccinia virus DNA was detected in the ESP rinsate and from the 3M™ portion of all the FASST Mk II collector samples. Replicate samples were collected for the rinsate and 3M™ filter collection system and PCR recovery is presented as an average for each sample and target ( FIGS. 25  an  26 ). Data for Sample 8 is included in the graph although a malfunction occurred during the experiment. Approximately 30 seconds into the collection, the ESP unit shut down and the interlock light turned off. Due to the incomplete collection of SRM, the bar graph for that data point contains hash marks to differentiate the data from the other 7 sample points. 
     Results indicate that a portion of the targets of interest are passing through the ESP and collected in the 3M™ filter. Target recovery between the rough tile and carpet surfaces were similar but there was a noticeable difference in the data between the two targets when analyzing the ESP rinsate versus 3M™ filter. In several of the Vaccinia samples the Ct, values for the 3M™ filter indicate better recovery of the target when compared to the ESP rinsate. The Ct values for the  B. anthracis  target are more similar between the rinsate and 3M™ filter with less variability. 
     Results from the standard COTS 3M™ collections show nearly equivalent recovery of the spore and virus targets from the filter (See  FIG. 27 ). Sample loss from filters that were pre-processed for live culture lost an average of 2 Cts when compared to filters that were processed only for nucleic acids. When PCR results from the COTS 3M™ ( FIG. 27 ) and the FASST 3M™ filter data ( FIGS. 25 and 26 ) are compared better recovery of the virus target is noted from the FASST Mk II 3M™ filter. An order of magnitude more target of the virus was recovered from the FASST 3M™ filter than from the COTS system 3M™ filter. The spore target was recovered comparably between the two filters. 
     Viable  B. anthracis  Sterne spores were recovered from all ESP inner tube rinsate samples from rough tile and carpet collections (See  FIG. 28 ). Data for Sample 8 is included in the graph although a malfunction occurred during the experiment which significantly impacted target recovery. The purple bars represent live culture recovery from representative standard 3M™ vacuum collections using a protocol provided by DHS and described earlier. With the exception of sample 8, there was no significant difference in live culture recovery of viable  B. anthracis  between samples. Comparable recovery of target was achieved using the DHS rinsate protocol from 3M™ filters. 
     These characteristics are embodied in the FASST Mk II collector with the following benefits:
         1. High collection efficiency of particles within the 0-40 μm size range of interest.   2. Segregation of 0-40 μm particles from heterogeneous real world samples.   3. Equivalent spore recovery when compared to the COTS 3M™ system.   4. Enhanced viral recovery when the Mk II collector is coupled with the COTS 3M™ system.   5. Two week room temperature sample stability on the Mk II ESP tube supporting operational requirements.   6. Minimized sample processing time for viable organisms.       

     Capacity testing of the FASST Mk II collector with a variety of sample types demonstrated high collection efficiency when the sample is within the target particle range and successful size segregation when the sample is of a highly heterogeneous nature. Of the sample types tested, the FASST Mk II collector had the highest collection efficiency with the collection of Standard Reference Material (SRM) which has a particle size range of 0-40 μm. Over 80 percent of the total SRM sample was collected in the sample collection tube and over 98 percent of the total sample was recovered within the MK II component parts. The collector worked exceptionally well over the entire range of sample SRM dust loading quantities from 0.5 g-10 g. The most challenging sample type for the ESP was the auto debris. In this test the sample collection tube caught an average of 19% of the total sample mass, with four of the eight tests having lower than 19% of the total sample captured in the sample collection tube. This behavior is expected, given that auto debris is primarily made up of larger particles (average size=500 □m) that the ESP has been specifically designed to not capture. 
     The collection nozzle  36  presented a source of sample loss due to caking action of the very fine particulates encountered with Ultra-Fine Arizona Road Dust (1-10 μm) and was also a site of debris clumping in the case of large particles. Large particulates or clumps of gathered debris tended to adhere to the nozzle grating or become matted on the front of the nozzle. A design modification to the collection nozzle to incorporate a coarse filter or internal grating may overcome this limitation. 
     Pre-validation test results of the FASST Mk II collector demonstrated repeatability and consistency between replicate sample collections as demonstrated by recovery of nucleic acid and viable target. Target recovery from the rough tile and carpet surfaces were consistent between collections. The spore target was recovered from the ESP collection tube and from the downstream 3M™ filters at equivalent levels, although more variability was noted in collections from the rough tile surface. Live culture data for  B. anthracis  was relatively consistent between sample collections and comparable to the current DHS live culture recovery from 3M™ filters. The virus target was consistently recovered to a higher degree from the downstream filter than from the ESP sample collection tube. Significantly more virus (by an order of magnitude) was recovered from the FASST 3M™ filter than from the COTS 3M™ filter and when combined with target recovered from the ESP collection tube, the FASST Mk II collector provides significantly more target for analysis from its component collection tube and 3M™ filter components. 
     The primary benefit of the FASST collector is its ability to efficiently collect small particles within the size range of biological organisms for rapid recovery in a pre-coated collection vessel designed to stabilize collected organisms and promote rapid live culture recovery. Laboratory stability testing demonstrated two-week stability of vacuum collected samples held at room temperature for recovery of nucleic acid signature and spores from the ESP tube which supports operational field requirements for post-collection sample stability. The FASST collection system provides end users with a unique collection system which greatly diminishes sample processing time particularly for viable organisms. The ability to expand in culture biological agents collected from a crime scene provides the opportunity to gather detailed microbiological analysis including biochemical analysis, serotyping, virulence determination, antibiotic susceptibility in additional to sequencing and genotyping data, critical data points to determine source attribution. 
     Overall, the FASST Mk II collector met the objectives of the second phase of the program, but laboratory testing and client feedback revealed key areas for improvement during Phase III of the FASST program. First, Applicant will refine the FASST Mk II collector by adding sample containment and extraction features that prevent the inadvertent release of captured biological particles during extraction and analysis. This will be accomplished by adding collection tube sample containment caps such as caps  42  and  44  ( FIG. 12 ) with injection/extraction ports. The user will install these caps in the field after the collection tube is removed. This feature will effectively eliminate potential re-aerosolization and exposure of captured sample to test facilities during the extraction and recovery process. Applicant will also improve the front end filter on the FASST Mk II collector. The purpose of this filter is to eliminate large material such as hairs and fibers from entering into the collection tube, reducing the concern of arcing and clogging within the ESP. However, testing of the FASST Mk II collector showed that this front end filter can itself become clogged, reducing airflow through the device. This debris is then difficult to recover for subsequent analysis. This front end filter will be redesigned in Phase III to eliminate these issues. Finally, minor changes to the electronics and user interface will be made to improve safety and ease of use. 
     FASST Mk III Design 
     The FASST MK III collector  46  is more clearly identified in  FIGS. 29-50 , this embodiment being constructed according to the teachings of the present invention.  FIG. 29  represents an exploded view of the FASST MK III collector  46  which includes a collection tube system  48 , a center case assembly  50 , a bottom sliding cover  52  and a handle assembly  54 . The collection tube assembly includes a tube module  56 , an intake nozzle  58  and a filter adapter  60 . An exploded cross-sectional view of the collector tube module  56  is best illustrated in  FIG. 30  and includes the collector tube  62 , the high voltage wire electrode  64 , a high voltage electrode  66  for insertion into a corresponding receptacle associated with the electronics housing, a front adapter  68  and a rear adapter  70 . The high voltage electrode  66  is associated with the rear adapter  70 . The collection tube  56  also includes a pair of silicon O-rings  72  as illustrated in  FIG. 30 , a tension spring  74 , a spring pin  76  and a spring cover  78 . The high voltage wire electrode  64  is appropriately suspended within the collector tube  62  between the rear bracket member  80  and the front tension spring  74 . The wire  64  extends through the front adapter  68  and attaches to the tension spring  74 . 
     The core technology in the FASST MK III collector  46  is the electrostatic precipitator (ESP) that employs a high voltage power supply  84  ( FIGS. 32A-D ) associated with the electronics package as will be hereinafter further explained which provides approximately 10,000 volts dc to the wire electrode  64  suspended within the collection tube. This configuration generates a corona discharge to ionize the sample air stream and create free electrons. Smaller (1-20 μm) particles entering the ESP collector tube module  56  encounter the ionization field, causing them to efficiently precipitate onto the collection tube wall  62 . Due to their inertia, larger particles pass through the ionization field and are captured by a secondary dry filter located downstream of the ESP. The 3M™ vacuum as previously explained with respect to the FASST MK II collector discussed above is the primary air mover for the FASST MK III collector as well. 
     An exploded view of the center case assembly  50  is best illustrated in  FIG. 31  and includes a center case housing  82 , a high voltage supply assembly  84 , a main electronics PC board including a microprocessor  86 , a rear Hall Effect PC board sensor  88 , a front Hall Effect PC board sensor  90  and a bottom Hall Effect PC board sensor  92 . The sensors  88 ,  90  and  92  are part of a safety mechanism or sensor system that protects the overall MK III collector  46  and the operator from damage and injury due to high voltage exposure as will be hereinafter further explained. The center case assembly  50  likewise includes a spring clip  94  positioned therewithin for engaging the collector tube assembly  48  when the assembly  48  is positioned within the center case assembly  50 . 
       FIGS. 32A ,  32 B,  32 C and  32 D illustrate top and side elevational views of the high voltage supply assembly  84  located within the center case assembly  50 . The high voltage supply assembly  84  includes a high voltage power supply  96  ( FIG. 32B ), a high voltage PC board  98  ( FIG. 32D ), a high voltage connector  100  ( FIGS. 32A and 32B ), and a high voltage potting case  102  ( FIG. 32C ). The high voltage supply assembly  84  provides the required DC volts to the wire electrode  64  for generating the corona discharge within the collector tube  62  to ionize the incoming sample air stream. The high voltage supply assembly  84  is located within the center case assembly  50  as best illustrated in  FIG. 31 . 
       FIG. 33  is a perspective view of the intake nozzle  58  associated with the collection tube assembly  48  illustrated in  FIG. 29 . The intake nozzle  58  includes an attachment portion  59  for cooperatively attaching to the front adapter portion  68  associated with collection tube module  56 . Any suitable cooperatively engageable means associated with both members  59  and  68  can be utilized to suitably engage the intake nozzle  58  to the front portion of the collector tube module  56 . As illustrated in  FIG. 33 , the cooperatively engageable means could be corresponding threads, a snap-fit arrangement, or a quarter-turn lock arrangement. The adapter portion  59  likewise includes a magnet  61  as best illustrated in  FIG. 33 . The front Hall Effect sensor  90  associated with the center case assembly  50  senses magnet  61  when the collector tube assembly  48  is properly positioned within the center case assembly  50  as will be hereinafter further explained. The intake nozzle  58  likewise includes a front-end screen/filter member  63  as best illustrated in  FIG. 29  that functions to eliminate large material such as hairs and fibers from entering into the collection tube  62  thereby reducing the concern of arcing and clogging within the ESP. 
       FIG. 34  is a perspective view of the filter adapter  60  associated with the collection tube assembly  48  illustrated in  FIG. 29 . The filter adapter  60  likewise includes an attachment portion  63  having cooperatively engageable means associated therewith for attaching to the rear adapter portion  70  associated with collection tube module  56 . Here again, any suitable type of cooperating means for attaching filter adapter  60  to member  70  associated with the collection tube module  56  can be utilized such as cooperating threads, a snap-fit, or a quarter-turn locking mechanism. The filter adapter  60  likewise includes a magnet  65  which is sensed by the rear Hall Effect sensor  88  associated with the sensor case assembly  50  when the rear portion of the collector tube assembly  48  is properly installed within the center case assembly  50  as will be hereinafter further explained. The attachment portion  63  of filter adapter  60  likewise includes a pair of magnet latches  67  which will mate and lock with a corresponding pair of magnet latches  104  associated with the bottom sliding cover  52  which is best illustrated in  FIG. 35 . The magnet latches  104  associated with the bottom sliding cover  52  will mate with and engage the magnet latches  67  associated with the filter adapter  60  when the collection tube assembly  48  is properly positioned within the center case assembly  50  and when the bottom sliding cover  52  is properly engaged with the track mechanism associated with the bottom portion of center case assembly  50 . The bottom sliding cover  52  likewise includes a magnet  106  which is likewise sensed by the bottom Hall Effect sensor  92  associated with the center case assembly when the bottom sliding cover  52  is properly engaged and installed within the center case assembly  50 . The magnets  61 ,  65  and  106  likewise form part of the safety mechanism or sensor system which protects the overall collector  46  and the operator from damage and injury due to high voltage exposure as will be hereinafter further explained. 
       FIG. 36  is an exploded perspective view of the handle assembly  54  illustrated in  FIG. 29 . The handle assembly  54  includes a handle member  108 , a battery clip holder  110 , a base member  112  and a user interface  114 . The FASST MK III collector  46  is powered by at least one off-the-shelf 12-volt lithium-ion battery enabling operation for up to at least 2 hours. The handle mounted battery (not shown) snaps in and out of the battery clip  110  for easy recharging or replacement. Replacement batteries are available at home improvement stores nationwide. LED indicators, status lights, power buttons and so forth are integrated into the single membrane user interface  114  as will be hereinafter further explained. The interface  114  includes an on-off button  116 , a COLLECT enable button  118 , a series of battery life status LEDs  120  and three LEDs  122 ,  123  and  125  indicating operational status. LED  122  is a collection status light and LEDs  123  and  125  are system error status lights as will be hereinafter further explained. When the handle assembly  54  is properly engaged with the center case assembly  50 , electrical contact with all of the electrical components associated with the FASST MK III collector  46  will be electrically coupled for operational use. 
     The Hall Effect sensors  88 ,  90  and  92  in conjunction with magnets  61 ,  67  and  106  provide several safety mechanisms or sensor systems that protect the unit and operator from damage and injury due to high voltage exposure. The FASST Mk III collector will not enable high voltage unless it is fully and properly assembled. There are three safety interlocks that will prevent high voltage from turning on if the full collection tube assembly  48  and bottom sliding door cover  52  are not fully and properly installed. Additionally, if either of these two components are removed from the unit during operation or become dislodged from their properly installed position, high voltage will immediately be disabled. The safety interlocks are in effect Hall Effect (magnetic) sensors  88 ,  90  and  92  that signal or communicate with the micro-processor when an ESP tube assembly  48  is properly installed and the safety cover or access door  52  is closed. As previously discussed, the Hall Effect sensors  88 ,  90  and  92  sense the proper position of the respective magnets  61 ,  65  and  106  associated with the intake nozzle  58 , the filter adapter  60  and the bottom sliding door cover  52  when all of these components are in their proper installed position. If any one of these components is not properly installed, the appropriate Hall magnet sensor system will not read its associated magnet and therefore will prevent high voltage from turning on, or it will disable high voltage if the collection process has already started. The respective magnets  61 ,  65  and  106  are positioned and located such that the respective Hall Effect sensors  88 ,  90  and  92  will be able to read and sense the magnet when its corresponding component is properly installed and positioned within the center case assembly  50 . In other words, the sensors  88 ,  90  ad  92  sense the proper position of the intake nozzle  58 , the filter adapter  60  and the access door  52  within the center case or housing assembly  50  and communicate with the microprocessor  86  to prevent high voltage from being supplied to the electrode wire  64  if any of these components are not properly installed or positioned within the housing assembly  50 . This safety mechanism is indicated by the yellow safety LED  125  and red system LED  123  as will be hereinafter further explained. Under normal conditions, the yellow safety LED  125  and red high voltage (HV) error LED  123  are off. It will blink in different patterns if any component is missing from the unit as explained below. The switches are hidden from the user&#39;s sight within the electronics enclosure  50  to reduce the likelihood of a user circumventing the safety interlocks. 
     The electronics and microprocessor  86  in the Mk III collector  46  receive feedback from the internal high voltage power supply  84 . Excessive current draw, under voltage, and excessive power supply temperature are all monitored by appropriate sensors and can be signs of a possible electrical short or other malfunction. For example, the high voltage power supply  96  includes (1) a current sensor for monitoring excessive current draw from the high voltage power supply assembly  84 ; (2) a voltage sensor for monitoring under voltage from the high voltage power supply assembly  84 ; and (3) a temperature sensor for monitoring excessive temperature of the high voltage power supply  96 . The high voltage power supply  96  will be shut down if any of these scenarios are detected. This will be indicated by blinking operational status LEDs  123  and  125  as will be hereinafter further explained. 
     When the 12 volt battery is installed, the operator will press and hold the ON/OFF button  116  for three seconds to power on the unit. After three seconds, all three battery life status LEDs  120  will turn on steady, while the three operational status LEDs  122 ,  123  and  125  will blink, simultaneously for 5 seconds, indicating the power on sequence. Once the blinking stops, the green battery life status LEDs  120  (either one, two, or all three, depending on available battery life) will remain on constant. To enable collection, the operator will press and hold the COLLECT button  118  for three seconds. The collection status LED  122  will then remain on steady as long as high voltage is being supplied to the FASST Mark III&#39;s electrostatic precipitator and the unit is functioning properly. There are two options to disable collection. The first option is to press the collect button  118 . The collection status LED  122  will then turn off. The second option is to press the on/off button  116  which will disable collection and power off the entire unit. 
     The FASST Mark III has three battery life status LEDs as seen in  FIG. 36 . These LEDs are used to indicate available battery life and provide a warning as to when the FASST Mark III collector will automatically shut down due to low available battery power. Table 8 shows which LEDs will display at different battery voltage ranges. As the FASST Mark III battery life drops below 9.8V, the last LED will blink very rapidly for five seconds before the unit powers down. 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Battery Life LED Status 
               
            
           
           
               
               
               
               
            
               
                 LEFT 
                 MIDDLE 
                   
                   
               
               
                 LED 
                 LED 
                 RIGHT LED 
                 DESCRIPTION 
               
               
                   
               
               
                 OFF 
                 OFF 
                 OFF 
                 POWER OFF 
               
               
                 BLINKING 
                 OFF 
                 OFF 
                 BATTERY VOLTAGE &gt;9.8 V 
               
               
                   
                   
                   
                 AND &lt;10.3 V 
               
               
                 ON 
                 OFF 
                 OFF 
                 BATTERY VOLTAGE &gt;10.3 V 
               
               
                   
                   
                   
                 AND &lt;10.8 V 
               
               
                 ON 
                 ON 
                 OFF 
                 BATTERY VOLTAGE &gt;10.8 V 
               
               
                   
                   
                   
                 AND &lt;11.3 V 
               
               
                 ON 
                 ON 
                 ON 
                 BATTERY VOLTAGE &gt;11.3 V 
               
               
                   
               
            
           
         
       
     
     The three Hall Effect safety mechanisms ( 88 ,  90 ,  92 ,  61 ,  67  and  106 ) discussed above will protect the unit from damage and the operator from injury due to high voltage. The Mark III collector will not enable high voltage unless it is fully assembled as discussed above. Additionally, if any of these components are removed from the unit during operation, or become dislodged from their properly installed position, high voltage will be immediately disabled. This safety mechanism is indicated by the yellow SAFETY ERROR LED  125 . Under normal conditions, the yellow LED  125  and red LED  123  are off. They will blink in different patterns if any component is missing from the unit. If the yellow LED  125  and/or red LED  123  are blinking, the user needs to ensure that all the components of the FASST Mark III collector are fully assembled. The electronics in the Mark III collector receive feedback from the internal high voltage power supply  96 . As previously explained, excessive current draw, under voltage, and high voltage power supply temperature are all monitored by various sensors or other systems and these sensors communicate with the microprocessor to shut down the high voltage power supply  96  if any of these scenarios are detected. This will be indicated by a blinking red HV ERROR LED  123  for an excessive current draw or under voltage and a blinking red HV ERROR LED  123  and steady on yellow LED  125  for an overheating scenario. Table 9 below shows all possible LED status scenarios for the FASST Mark III collector. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 LED Status Indicator Table 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 COLLECTING 
                   
               
               
                 SAFETY ERROR 
                 HV ERROR 
                 (AMBER 
               
               
                 (YELLOW LED) 
                 (RED LED) 
                 LED) 
                 DESCRIPTION 
               
               
                   
               
               
                 OFF 
                 OFF 
                 ON 
                 COLLECTING WITH NO ERRORS 
               
               
                 OFF 
                 OFF 
                 OFF 
                 POWERED OFF 
               
               
                 BLINK SLOW 
                 BLINK 
                 BLINK SLOW 
                 POWER UP SEQUENCE 
               
               
                   
                 SLOW 
               
               
                 BLINK SLOW 
                 OFF 
                 OFF 
                 DOOR OPEN 
               
               
                 BLINK FAST 
                 OFF 
                 OFF 
                 INTAKE NOZZLE OUT OF 
               
               
                   
                   
                   
                 POSITION 
               
               
                 BLINK FAST 
                 ON 
                 OFF 
                 FILTER ADAPTOR OUT OF 
               
               
                   
                   
                   
                 POSITION 
               
               
                 OFF 
                 BLINK 
                 OFF 
                 HV CURRENT ERROR 
               
               
                   
                 SLOW 
               
               
                 OFF 
                 BLINK FAST 
                 OFF 
                 HV VOLTAGE ERROR 
               
               
                 ON 
                 BLINK 
                 OFF 
                 HV OVER TEMP 
               
               
                   
                 SLOW 
               
               
                   
               
            
           
         
       
     
     Removing the collection tube assembly  48  for analysis takes less than 20 seconds and is a tool-free process. Sample recovery protocols have been developed to efficiently remove viable biological agents and nucleic acids from the collector&#39;s coated (trehalose/betaine) surface  62  to enable live culture and molecular analysis of sample extracts recovered from the system. The FASST MK III device contains sample containment and extraction features that prevent the inadvertent release of captured biological particles during extraction and analysis via collection tube sample containment caps  124  and  126  with injection/extraction ports as best illustrated in  FIG. 37 . The end-user installs these caps in the field after the collection tube is removed. 
       FIG. 37  is a perspective view of the collector tube module  56  in both its collection configuration and its containment configuration. The collection configuration is likewise illustrated in  FIG. 29  and is the collection tube assembly  48 . As indicated above, once collection is complete, the end-user or operator will remove the collection tube assembly  48  from the center case assembly  50  by opening the bottom sliding access door cover  52  and removing the collection tube assembly  48  therefrom. Once the collection tube assembly  48  is removed from the overall device, the inlet nozzle  58  is removed and replaced with containment cap  124  and the filter adapter  60  is removed and replaced with containment cap  126 . Containment cap  124  likewise includes an injection/extraction port  128  wherein a buffer solution can be injected into the collection tube  56  to help preserve the biological material collected therein. Removal or extraction of the biological material collected within the collection tube  56  is likewise extracted through the same injection port  128 . This feature effectively eliminates potential re-aerosolization and exposure of captured sample to test facilities during the extraction and recovery process. In addition, the collector tube assembly  48  includes a front end screen  63  that functions to eliminate large material such as hairs and fibers from entering into the collection tube, again reducing the concern of arcing and clogging within the ESP. 
     Assembly of both the collection tube assembly  48  and the entire FASST MK III collector  46  is set forth below and illustrated in  FIGS. 38-50 . The step-by-step attachment process as well as use of the MK III collector  46  is as follows. 
     Collection Tube Assembly 
     1. Attach the intake nozzle  58  and the filter adapter  60  to the collection tube module  56 . See  FIGS. 38 and 39 . 
     FASST Mark III Unit Assembly 
     1. Insert the Collection Tube Assembly  48  into the Electronics Housing or center case assembly  50 . Ensure that the high voltage electrode  66  ( FIG. 40 ) on the Collection Tube Assembly  48  is inserted into the high voltage receptacle  130  ( FIG. 41 ) on the Electronics Housing/center case assembly  50 . See  FIG. 42  for complete assembly of collection tube assembly  48  and its housing  50 . 
     2. Attach the bottom sliding access cover  52 , which is secured in place by a magnetic latch  67 ,  104  ( FIGS. 43 ,  44  and  45 ). 
     3. Plug the 12 volt battery in the FASST Mark III collector  46  ( FIGS. 46 and 47 ). 
     Full System Assembly 
     1. Slide the 3M™ vacuum choke  40  into the end of the 3M™ trace Evidence Vacuum hose  12  ( FIG. 48 ). 
     2. Attach the 3M™ Dry Filter  14  to the 3M™ Trace Evidence Vacuum Hose/Choke Assembly ( FIG. 49 ). 
     3. Attached the complete hose assembly to the FASST Mark III collector ( FIG. 50 ). 
     how to Successfully Use the System 
     1. When the 12 volt battery is installed, press and hold the ON/OFF button  116  for three seconds to power on the unit. After three seconds, all three battery life status LEDs  120  will turn on steady, while the three operational status LEDs  122 ,  123  and  125  will blink simultaneously for 5 seconds, indicating the power on sequence. Once the blinking stops, the green battery life status LEDs  120  (either one, two, or all three, depending on available battery life) will remain on constant. To enable collection, press and hold the COLLECT button  118  for three seconds. The collection status LED  122  will remain on steady as long as high voltage is being supplied to the FASST Mark III&#39;s electrostatic precipitator and the unit is functioning properly. 
     2. There are two options to disable collection. The first is to press the COLLECT button  118 . The collection status LED  122  will turn off. The second is the press the ON/OFF button  116 , which will disable collection and power off the unit. 
     3. After collection, disassemble the unit in reverse order as discussed during assembly above. Remove the collection tube assembly  48 , remove the inlet nozzle  53  and cap with the front containment cap  124 ; remove the rear filter adapter  60  and cap with the rear containment cap  126 . 
     4. Add 6-mL of PBS to the collection tube  56  via injection port  128 . 
     5. Vortex and extract PBS buffer via the same injection port  128 . 
     6. The sample is now ready for biological analysis via live culture/PCR. 
     Tube Coating Long Term Stability Study 
     The tube coating, like any other organic or chemical substance, can undergo chemical changes (e.g. degradation, oxidation), and/or physical changes (e.g. delamination, flaking, crystallization) over time. The stability study identified how those changes altered the efficacy of the formulated coating solution and the timeframe associated with those changes. Another study goal was to identify the time duration at which the tube can no longer be used when stored at two specific temperature conditions. 
     Applicant cleaned fifty-eight (58) 6061 Aluminum (Al) tubes to evaluate the stability of the coating. Fifty new Al tubes were cleaned with the modified cleaning SOP presented below and were used for the first 5 time points. These Al tubes were purchased on Phase II of this program and had not been coated prior to this study. The remaining eight (8) tubes were Phase I Al tubes cleaned and re-coated for the last time point. Applicant prepared a fresh trehalose/betaine solution prior to cleaning the Al tubes. Initially, staff followed the draft SOP developed under Phase I of the FASST program to clean the tubes. However, once issues were noted with coating the new 6061 Al material, the draft SOP was slightly modified to the procedure outlined below: 
     1. Prepare an aqueous solution of D-Greeze AC Z603 (Solvent Kleene); one (1) part AC Z603 to five (5) parts distilled water 
     2. Place 6061 aluminum alloy tubes, on end, in 2 L glass beaker 
     3. Cover aluminum tubes with the diluted D-Greeze solution 
     4. Place 2 L glass beaker in ultrasonic bath 
     5. Ultrasonicate aluminum tubes for 30 minutes 
     6. Remove aluminum tubes, rinse with distilled water, and place on clean kimwipe 
     7. Place 6061 aluminum alloy tubes, on end, in 2 L glass beaker 
     8. Cover aluminum tubes with methanol 
     9. Place 2 L glass beaker in ultrasonic bath 
     10. Ultrasonicate aluminum tubes for 30 minutes 
     11. Remove aluminum tubes and place on clean kimwipe 
     12. Place aluminum tubes, on end, in 2 L glass beaker 
     13. Cover aluminum tubes with acetone 
     14. Place 2 L glass beaker in ultrasonic bath 
     15. Ultrasonicate aluminum tubes for 30 minutes 
     16. Remove aluminum tubes and place on clean kimwipe 
     17. Allow tubes to air dry 5 minutes 
     18. Rinse tubes with water to remove residual acetone and physical debris 
     19. Place cleaned aluminum tubes in plastic zip-loc bags 
     Applicant then followed the draft SOP developed under Phase I of the FASST program to coat the tubes. The coating steps are provided in brief below: 
     1. Turn heated roller equipment on and verify that the rollers are rotating and heating 
     2. Turn heated roller equipment to 125° C. setting 
     3. Verify temperature was at least 50° C. 
     4. Turn on heat gun to high setting and aim just above heated rollers 
     5. Place black plastic caps onto both ends of 12 clean aluminum tubes 
     6. Use Eppendorf pipettor to place 7 mL trehalose/betaine (aq) solution into each aluminum tube (two additions of 3.5 mL each) 
     7. Roll aluminum tube slowly multiple turns to ensure the coating solution properly wetted the entire inner aluminum diameter 
     8. Visually verify that all interior surfaces were wetted and retained wetness 
     9. Place 12 aluminum tubes containing coating solution onto the heated roller equipment 
     10. Heat aluminum tubes for 2.5 hours 
     11. Remove aluminum tubes from heat 
     12. Verify visually that internal aluminum surfaces were completely coated (Note: 6061 Al alloy uncoated sections will appear gold) 
     13. Place fully coated aluminum tubes in plastic zip-loc bag 
     14. Place one dessicator package into plastic zip-loc bag 
     15. Place one humidity indicator card into plastic zip-loc bag 
     16. Remove air from zip-loc bag with vacuum 
     17. Seal zip-loc bag and placed in dry storage 
     Table 10 summarizes the test matrix used to evaluate the coating stability. Two environmental conditions (5° C. and 30° C.) were created for each of the six (6) time points (1-24 weeks), with the first five (5) time points having five (5) replicate tubes to evaluate. Applicant evaluated only four (4) replicate tubes at the 24-week time point due to complications with initially coating the raw Al material. Eight (8) spare Al tubes used in Phase I were cleaned and re-coated to reduce the schedule delay caused by modifying the tube cleaning SOP. 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 Sample Matrix for Stability Study 
               
            
           
           
               
               
            
               
                   
                 Parameter 
               
            
           
           
               
               
               
               
               
            
               
                   
                 # of Samples 
                 Time Point 
                 Humidity 
                 Temperature 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 5 
                 1-week 
                 &lt;5% 
                  5° C. 
               
               
                   
                 5 
                   
                   
                 30° C. 
               
               
                   
                 5 
                 2-week 
                 &lt;5% 
                  5° C. 
               
               
                   
                 5 
                   
                   
                 30° C. 
               
               
                   
                 5 
                 4-week 
                 &lt;5% 
                  5° C. 
               
               
                   
                 5 
                   
                   
                 30° C. 
               
               
                   
                 5 
                 8-week 
                 &lt;5% 
                  5° C. 
               
               
                   
                 5 
                   
                   
                 30° C. 
               
               
                   
                 5 
                 16-week  
                 &lt;5% 
                  5° C. 
               
               
                   
                 5 
                   
                   
                 30° C. 
               
               
                   
                 4 
                 24-week  
                 &lt;5% 
                  5° C. 
               
               
                   
                 4 
                   
                   
                 30° C. 
               
            
           
           
               
               
               
            
               
                   
                 58 
                 Total Number of Samples 
               
               
                   
                   
               
            
           
         
       
     
     At each time point, tubes were removed from the environmental chamber and inspected. The coating mass was determined by weighing the coated tube after storage and subtracting the uncoated Al 6061 tube mass. Differences in coating weights are due to water absorption, slight coating solution volume differences, and mass loss when removing the end caps for visual inspection. Visual defects were noted by Applicant. Crystallization appears as an opaque region when observed at an oblique angle relative to a light source. All coatings were noted as continuous with no observable coverage gaps. Flaking, or coating delamination, was not observed even after a 15 minute, 400 liter per minute flow test. Film thicknesses were measured with a calibrated Positector 6000 acoustic film measurement device. Three measurements were taken approximately 2 cm from both tube ends. The reported values are averages of the three replicate measurements for each tube end. 
     Applicant conducted the Storage Stability Test to determine how temperature and time impacted coated tube shelf life. 
     The initial test hypothesis that crystallization may cause problems due to delamination and fragility were not supported at any time points. Crystallization was evident from the onset of coating deposition and did not significantly worsen over time. Coated tubes did not lose significant mass during air flow tests after being stored for time periods up to, and including, 24 weeks. The last time point indicated water was being absorbed by the films and was possibly due to the dessicant packet reaching saturation. Tubes performed similarly under either storage temperature with humidity being controlled by the packaging configuration (i.e. low water permeability plastic bags and a dessicant package). 
     Applicant recommends continuing to package coated ESP tubes in vacuum-sealed plastic zip-loc bags with a dessicant packet and humidity indicator card. The packaging will reduce the amount of water the tubes are exposed to and allow chain-of-custody and contamination/tamper seal concerns to be addressed. Applicant concludes that ESP tubes can be used without performance impact for at least 24 weeks when stored between 5-30° C. There were indications that storage durations longer than 16 weeks may cause excessive water absorption that could result in re-liquefying the trehalose coating. Longer storage periods may be possible if additional dessicant packets were inserted into the packaging. 
     Coating crystallization does not impact coating delamination as initially theorized. Applicant observed crystallization occurring prior to placing the coated tubes within a sealed plastic package. Applicant has determined that the crystallization was caused by using heat to evaporate the water from the coating solution. Heat is not required for coating the tubes but it does reduce the process time for better manufacturability. Applicant has proposed to identify alternative techniques to scale-up coated tube production for a Phase III effort. 
     The tube coating studies have revealed three (3) main characteristics that one should look for in potential coatings, namely: 
     1. Compatibility with the intended collection target; 
     2. Water solubility—enable simple extraction off of the ESP tube; 
     3. Surface wetting—the coating must wet the tube evenly to enable a thin uniform thickness coating. 
     The thin uniform coating is necessary to ensure proper collection performance and that the coating can be rinsed with a minimal volume of water. One can tweak the wettability by changing tube materials if necessary (note: wetting properties are based on the combination of the coating and the tube material). In general, many different sugar based coatings will work well. Illustrative saccharides include, but are not limited to, glucose, fructose, galatose, ribose, trehalose, sucrose, lactose, maltose, cellobiose, raffinose, hydrophilic polysaccharides, and mixtures thereof. Trehalose works particularly well in the present coating solution. Gelatin based coatings have also been used successfully in the past as well. 
     Improved FASST Mk III Design 
     The improved FASST MK III collector is substantially similar to the FASST MK III collector  46  described in detail above except that it includes two additional features, namely, an automatic altitude adjustment feature and an electrostatic discharge feature. In all other respects, the construction and operation of the improved MK III collector will be substantially identical to the components, features and operation of the MK III collector  46  discussed above and illustrated in  FIGS. 29-50 . 
     Automatic Altitude Adjustment 
     The automatic altitude adjustment feature associated with the improved MK III collector is related to automatically adjusting the collection system settings to optimize performance at varying altitudes. The electrostatic method employed by the present FASST system relies on a corona discharge to ionize the air stream and ultimately charge and collect the incoming particulates. The actual corona onset voltage produced by the high voltage supply assembly  84  is a function of many environmental variables such as temperature, humidity, air pressure, as well as geometric variables such as the radius of the electrode wire  64 . The improved MK III collector automatically adjusts the electrode voltage based on atmospheric pressure measurements from an onboard pressure sensor. This feature is important since the corona onset voltage can vary by several thousand volts depending upon whether the system is used at sea level or in mountainous regions. Omission of the altitude feedback mechanism could result in either excessive arcing and electrical power draw at high altitudes or reduced collection efficient at lower altitudes. 
     The required voltage supplied to the wire electrode  64  in order to generate corona discharge to ionize the incoming air stream will decrease as altitude increases. In the present configuration, a pressure sensor is utilized to read atmospheric pressure. The pressure sensor is presently located on the main PC board  86  ( FIG. 31 ) but such sensor could be located anywhere on the device so long as it is exposed to atmospheric pressure. The pressure sensor reads the pressure and then the altitude adjustment circuitry associated with the main PC board  86  uses a look-up table stored in memory to adjust the electrode voltage based on the measured atmospheric pressure. The look-up table converts the atmospheric pressure to an altitude and then associates a predetermined voltage with such altitude. An altitude range and high voltage adjustment table such as Table 11 set forth below correlates specific altitude ranges with a specific high voltage. Depending upon the specific altitude at which the improved MK III collector is being used, the high voltage power supply  96  will provide the appropriate voltage to the electrode to establish the necessary ionization field. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Altitude Range and High Voltage Adjustment Table 
               
            
           
           
               
               
               
            
               
                   
                 Altitude Range 
                 Voltage 
               
               
                   
                 (feet above sea level) 
                 (volts) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                    0-9,999 
                 10,000 
               
               
                   
                 10,000-11,249 
                 9,500 
               
               
                   
                 11,250-12,449 
                 9,000 
               
               
                   
                 12,450-13,749 
                 8,500 
               
               
                   
                 13,750-15,000 
                 8,000 
               
               
                   
                   
               
            
           
         
       
     
     This automatic altitude adjustment feature can be incorporated into any of the other embodiments of the FASST collector including the MK II collector illustrated in  FIGS. 8-12  as well as the MK III collector  46  illustrated in  FIGS. 29-50 . 
     Electrostatic Charge Dissipation 
       FIGS. 51 and 52  are cross-sectional views of the collection tube module  130  of the improved MK III collector which includes a bundle of fine-tipped electrical conductors  132  which functions as a static discharge wire similar to that use on aircraft. Transition from a FASST system that uses alternating current power from grounded electrical outlets to a battery powered system such as the MK III collector system requires modifications to prevent excessive electrostatic charge build-up during use. A static discharging element  130  is introduced into the collection tube itself as illustrated in  FIGS. 51 and 52 . This technology is based on the static dischargers commonly used on aircraft. In the aircraft application, electrostatic charge builds on the aircraft during flight primarily due to triboelectric effects as the aircraft flies through the air. Aircraft typically use static dischargers on the trailing edges of the wing and fuselage to bleed excess charge off of the aircraft and back to the airstream. Without these static dischargers, the excess charge on an aircraft could lead to electrical noise that interferes with aircraft communication systems. 
     The improved MK III collection tube  130  includes a bundle of fine-tipped electrical conductors  132  inside the collection tube  130  to perform a similar function. The conductors  132  are electrically connected to the collection tube at point  134  and a holder member  136  to hold the opposite end of the static discharge wire  132  is positioned at the center of the rear portion of the tube as illustrated in  FIGS. 51 and 52 . This technique aids in the dissipation of excess charge which may accumulate on the collection tube and bleeds off this excess charge back into the airstream entering the dry filter  14  and vacuum hose  12 . Without the static discharge wire  132  placed inside the collection tube module  130 , a battery powered system collecting large amounts of dry dust in low humidity conditions may build up enough of a charge to shock the user within seconds of operation.  FIG. 53  is a perspective view of one end portion of the static discharge wire  132  held in its proper position by holder member  136  and  FIG. 54  is a cross-sectional view of  FIG. 53  showing one end portion of the static discharge wire electrically connected to the collection tube at point  134  and its opposite end portion held in proper position by holder member  136 . The static discharge wire  132  is illustrated in  FIG. 54  without any surrounding insulation so as to highlight the bundle of fine-tipped connectors associated with the discharge end portion. This arrangement of a bundle of fine-tipped connectors at the discharge end portion aids in the dissipation of excess charge which may collect on the collection tube module  130 . 
     It is recognized and anticipated that the electrical discharge wire  132  and holder  136  can be utilized and incorporated into the other embodiments of the present FASST collector including the MK II collector. 
     Thus there has been shown and described several embodiments of a FASST collector system and construction which provides improved ability to compartmentalize small particles within the size of biological organisms for rapid recovery from a collection vessel, which constructions fulfill all of the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the present invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention as described herein.