Abstract:
A capillary sampling array comprises a closely packed array of capillaries having any interstitial spaces therebetween filled with a material physically and mechanically compatible with the material from which the capillaries are formed and an outer jacketing material covering the closely packed array of capillaries.

Description:
BACKGROUND  
       [0001]     Many trace monitoring applications use sampling tubes to collect and concentrate a representative sample. A sample may comprise a matrix such as air or stack gas or some other fluid containing traces of impurities. The objective of collecting a sample in this manner is to increase the mass of the hazardous compounds of interest so that they can be separated, detected and reported. This technique can be used to detect the presence of, for example, chemical warfare agents (CWAs), explosives, or toxic industrial compounds (TICs). Such compounds are often referred to as “target” compounds. Typically, the inside of the sampling tube is coated with or contains a material that is suitable for trapping the target compounds for which the matrix is being monitored.  
         [0002]     In an instrumentation system that is used to monitor an industrial facility that may leak hazardous substances (e.g., a facility that is disassembling and disposing chemical weapons), a variety of instruments may be deployed throughout the plant and its environs. Where traces of toxic compounds in air, for example, may be present along with other compounds either from the plant or from the background air, the preferred instrument package is an air concentrator/desorber connected to a gas chromatograph. This type of instrument package is deployed throughout the facility in a variety of locations where workers may be present. These locations include areas of the plant where the toxic compounds are only occasionally present and then only at very low levels, areas where the toxic compounds are more frequently present and, if present, may be encountered at hazardous levels, and areas around the perimeter of the plant. Perimeter monitoring is normally done by collecting samples of air at various locations around the periphery of the facility. These samples are returned to the laboratory and analyzed to assure that emissions from the plant are below levels deemed to be hazardous to the general population as established by regulatory authorities. These air samples are analyzed using, for example, gas chromatography to detect the presence and amounts of hazardous substances. In many of these situations, the ability to rapidly collect the air sample, and rapidly analyze it is extremely important. In order to protect the workers from undue exposure the regulatory authority may require that the total sampling, analysis and reporting time be less than or equal to a predetermined time (e.g., 10 minutes). An instrument package of this type is referred to as a Near-Real-Time or NRT analyzer.  
         [0003]     To collect the substances in the air sample, an air sampling tube is typically packed with a porous polymer column packing material referred to as “TENAX,” a trademark of Tenax Fibers, GMBH &amp; Co., comprising polybiphenylene oxide. The TENAX is typically loaded into the tube in the form of a particle bed along with a secondary bed of a material such as HayeSep® Q to backup the TENAX and prevent breakthrough of the compounds of interest. HayeSEP® is a registered trademark of Hayes Separations, Inc. After the air sample is collected by the air sampling tube, the sample is desorbed to release the collected substances trapped in the air sampling tube. The desorption process may require multiple steps to liberate the collected substances from the TENAX particle bed. For example, the sample can be first desorbed onto what is referred to as a “focusing trap” to liberate and further concentrate any target compounds from the inside of the air sampling tube. The focusing trap may also contains TENAX. In this case the collected volatile compounds are transferred to the focusing trap by rapidly heating the sample tube to approximately 250° C. Then, the sample must be transferred from the focusing trap to a chromatographic column. This is performed by reversing the direction of trap flow and again heating the trapped compounds in the focusing trap to liberate them from the TENAX, while holding the chromatographic oven at a constant initial temperature that is low enough to focus the target compounds in a narrow band on the column. Unfortunately, this process requires at least two heating and cooling cycles, is time consuming, and often results in some of the collected substance remaining in the TENAX. Furthermore, TENAX is subject to degradation by reaction with water and polymerizable background compounds in the sample. This necessitates a dewatering step in which dry nitrogen or other such gas flows through the sample bed for a prescribed period of time. This multiple step process can adversely lengthen the time interval during which the workers may be inadvertently exposed to the presence of hazardous target compounds in the plant air without anyone being aware of it. Losses can also occur in the adsorption/desorption process for a variety of reasons, including possibly the reaction of the target compounds with water vapor or the adsorption of the target compounds onto active sites within the sampling system, which results in a reduction of the amount of collected substance entering the chromatograph. This in turn leads to low readings or in the worst case false negative results.  
         [0004]     Therefore, it would be desirable to transfer the collected volatile substances directly to a chromatographic column in one step, and to rapidly perform a sample/desorption cycle.  
       SUMMARY OF INVENTION  
       [0005]     According to one embodiment, a sample trap comprises a closely packed array of capillaries having any interstitial spaces therebetween filled with a material physically and mechanically compatible with the material from which the capillaries are formed and an outer jacket of the same material covering the closely packed array of capillaries so that the tube array can be installed and pressurized inside a thermal desorption device.  
         [0006]     Other aspects and advantages of the invention will be discussed with reference to the figures and to the detailed description of the preferred embodiments. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0007]     The invention will be described by way of example, in the description of exemplary embodiments, with particular reference to the accompanying figures in which:  
         [0008]      FIG. 1  is a schematic view illustrating a capillary tube constructed in accordance with an embodiment of the invention.  
         [0009]      FIG. 2A  is a schematic diagram illustrating a cross section of a partially complete capillary array constructed in accordance with an embodiment of the invention.  
         [0010]      FIG. 2B  is a schematic diagram illustrating a cross section of a complete capillary array constructed in accordance with an embodiment of the invention.  
         [0011]      FIGS. 3A and 3B  collectively illustrate a representative embodiment of a capillary array trap constructed in accordance with an embodiment of the invention.  
         [0012]      FIG. 4  is a schematic diagram illustrating the junction between a plurality of capillary tubes and the inside of the cladding of  FIG. 2B .  
         [0013]      FIGS. 5A and 5B  are a schematic diagram collectively illustrating portions of a six-port thermal desorption sampler (TDS) in both a sample ( FIG. 5A ) and a desorption ( FIG. 5B ) mode.  
         [0014]      FIGS. 6A and 6B  are a schematic diagram collectively illustrating an alternative embodiment of the thermal desorption sampler of  FIGS. 5A and 5B .  
         [0015]      FIGS. 7A and 7B  are a schematic diagram collectively illustrating another embodiment of the thermal desorption sampler of  FIGS. 5A and 5B .  
         [0016]      FIGS. 8A and 8B  are a schematic diagram collectively illustrating another embodiment of the thermal desorption sampler of  FIGS. 7A and 7B . 
     
    
     DETAILED DESCRIPTION  
       [0017]     While described below for use in collecting air samples, the low thermal mass multiple tube capillary sampling array, referred to hereafter as the “capillary array trap,” can be used to sample any fluid matrix, and to rapidly and efficiently release collected substances. In one example, the detection of trace amounts, on the order of 100 nanograms/meter 3 , of what is referred to as “mustard gas” is desired. It is desired to measure and report the presence of mustard gas in a five minute cycle, which includes sampling and analyzing the sample. Further, the capillary array trap can be used to sample liquid materials for desorption onto a liquid chromatograph.  
         [0018]      FIG. 1  is a schematic view illustrating a capillary tube  10  used to construct the capillary array trap of the invention. The capillary tube  10  is preferably fabricated from a glass material, such as, for example, borosilicate or Pyrex®. Each capillary tube  10  can have an outer diameter (OD) and wall thickness depending on the application. For example, each capillary tube  10  could have a diameter ranging between 100 and 250 micrometers (also referred to as “micron,” or μm). Each capillary tube  10  could have, for example, a five micron wall thickness. The individual tubes include an inner surface  13  coated with a passivation agent to prevent interactions between the sample and the tube walls as well as a material suitable for collecting sample substances. The material coating the inner surface  13  of each capillary tube  10  is referred to as a “trapping phase.” The trapping phase can have various compositions and thicknesses depending on the application. Further, the trapping phase can be a solid or a liquid. The passivation agent is typically a liquid. The thickness of the trapping phase applied to the inner surface  13  of each tube  10  depends on the material used as the trapping phase, and is generally applied as a thin film, approximately 1-10 microns thick. Other thicknesses, depending on the material used, are also possible. Solid phases can also be coated on the inside walls of the individual tubes for the purposes of trapping target compounds in the sample.  
         [0019]     Depending on the type of substance sought to be trapped in the capillary tube  10 , the trapping phase might be a polar material such as a polyethylene glycol, or might be a non-polar material such as dimethylpolysiloxane or an intermediate polarity phase such a 50% tricyanomethyl dimethylpolysiloxane. Essentially, the smaller the inner diameter of the tube, the higher the linear velocity of air through the array. Accordingly, whether a laminar flow or a turbulent flow occurs through the capillary tube  10  will affect the ability of the trapping phase inside the capillary tube  10  to capture the samples of material that are sought to be detected.  
         [0020]     The dimensions of the capillary tube  10  provided above are for exemplary purposes only. The length, wall thickness, inner diameter, outer diameter, material, and other parameters of the capillary tube  10  are arbitrary and variable.  
         [0021]      FIG. 2A  is a schematic diagram illustrating a cross section of a partially complete capillary array constructed in accordance with an embodiment of the invention using the capillary tubes  10  of  FIG. 1 . The capillary array  20  comprises a plurality of capillary tubes  10  packed in close proximity to each other surrounded by a cladding  25 . The cladding  25  can also be fabricated of a glass material of various thicknesses such as, for example, borosilicate glass or Pyrex®, and preferably has a wall thickness of approximately 250-500 microns. The interstitial spaces, an exemplary one of which is illustrated using reference numeral  18 , between the inner wall of the cladding  25  and the capillary tubes  10 , or between the capillary tubes  10 , is filled with a filler material  16  that is physically and mechanically compatible with the material from which the capillary tubes  10  are formed. For example, the filler material  16  can be, for example, glass rods  16  or another glass material that fuses and melts to the outside of the capillary tubes  10  when the capillary tubes  10  are formed into a capillary array  20 . The interstitial spaces  18  between the capillary tubes  10  are filled with a glass material  16  so as to eliminate the interstitial spaces  18  from the finished capillary array  20 . The capillary array  20  in  FIG. 2A  is shown partially complete so that the filling of the interstitial spaces  18  between the capillary tubes  10  can be shown.  
         [0022]     The structure of the capillary array  20 , and each capillary tube  10  ( FIG. 1 ), results in only the circular cross sections of the capillary tubes  10  ( FIG. 1 ) being exposed to the sample matrix flowing through the capillary array  20 . The dense packing of the capillary tubes  10  and the thin film trapping phase material applied to the inner surface  13  of each capillary tube  10  allows the capillary array  20  to trap and release collected substances in a single sample/desorption step. While show in  FIG. 2A  using 27 capillary tubes  10 , the number of capillary tubes  10  is arbitrary and, in one embodiment, a capillary array  20  would likely include approximately 200-500 individual capillary tubes  10 . However, a capillary array  20  may include from ten (10) to over 1000 individual capillary tubes  10 . The number of individual capillary tubes  10  is dependent upon, among other factors, the packing fraction obtainable based on the outer diameter of the capillary tubes  10  and the inner diameter of the cladding  25 . A packing fraction of at least 80% is reasonable.  
         [0023]      FIG. 2B  is a schematic diagram illustrating a cross section of a complete capillary array constructed in accordance with an embodiment of the invention. All the interstitial spaces  18  between the inner wall of the cladding  25  and the capillary tubes  10 , and between the individual capillary tubes  10 , are filled with a filler material  16 . In this manner, only the circular cross sections of the capillary tubes  10  are exposed to fluid flowing through the capillary array  20 .  
         [0024]      FIGS. 3A and 3B  collectively illustrate a representative embodiment of a capillary sampling array, sometimes referred to as a “capillary array trap” a “sample trap” or a “sample array” constructed in accordance with an embodiment of the invention. In one embodiment, the capillary sampling array  100  comprises a plurality of capillary tubes  10  densely packed into a capillary array  20  as shown in  FIG. 2B , and then formed into an approximate 6 mm, or 0.25 inch diameter capillary array trap  100 . The forming process is typically referred to as “drawing” in which the capillary array  20  begins at a diameter larger than the desired finished diameter, and is drawn, or extruded, possibly also heated, and reduced in diameter to the desired diameter. The drawing process melts the filler material  16 , thereby filling any interstitial spaces  18  between the capillary tubes  10  and between the capillary tubes  10  and the inner surface of the cladding  25 .  
         [0025]     A preferred length of the capillary sampling array  100  in this example is approximately 4.5 inches and can be, for example, 6 mm or 0.25 inch in diameter, depending upon application. However, the overall length and diameter of the capillary sampling array  100  is arbitrary and variable, depending on application. A capillary sampling array  100  may range from approximately 0.125 inch in diameter to over 0.5 inch in diameter, and the overall length of the capillary sampling array  100  may range from approximately 1 inch to three or four feet or more.  
         [0026]     The process of drawing the capillary array  20  down in diameter to form the capillary sampling array  100 , causes the filler material  16  in the interstitial spaces  18  between each capillary tube  10 , and the spaces  18  between each capillary tube  10  and the inside of the cladding  25 , to melt and form a single solid material surrounding each capillary tube  10 . In this manner, all fluid passing through the capillary sampling array  100  will travel through a structure having a circular cross section, i.e., each capillary tube  10  ( FIG. 1 ).  
         [0027]      FIG. 4  is a schematic diagram  200  illustrating the area between a plurality of capillary tubes  10  and the inside of the cladding  25  of  FIGS. 2A and 2B . As shown in  FIG. 4 , the filler material  16  fills all the spaces between the capillary tubes  10  and an interior surface  26  of the cladding  25 .  
         [0028]      FIGS. 5A and 5B  are a schematic diagram collectively illustrating portions of a six-port thermal desorption sampler (TDS)  300  in both a sample ( FIG. 5A ) and a desorption ( FIG. 5B ) mode. The thermal desorption sampler  300  includes a valve  302  having a valve body  304  and rotor  306 . The thermal desorption sampler  300  shown in  FIGS. 5A and 5B  is referred to as a “six-port” thermal desorption sampler with the six ports being a vacuum port  308 , a sample port  312 , a carrier gas port  314 , a column port  316 , a first port  342  of the capillary array trap  100  and a second port  344  of the capillary sampling array  100 . The temperature of the capillary sampling array  100  is controlled using a heater  334 . The vacuum port  308  is coupled to a vacuum source  326  through a flow controller  332 . A carrier gas source  318  is coupled through a flow controller  322  to the carrier gas port  314 .  
         [0029]     As illustrated in  FIG. 5A , during the sampling phase of the thermal desorption process, a vacuum  326  is applied via port  308  through a flow controller  332  to draw a sample  328  through the sample port  312  and through the port  344  into the capillary array trap  100  in the direction shown. For example, a vacuum of approximately 450 torr (approximately 0.7 atmosphere) is applied via the vacuum port  326  to fill the capillary array trap  100  with a sample fluid, in this example air.  
         [0030]     After the valve  302  is operated to fill the capillary sampling array  100  with a sample, it then switches to a desorption mode of operation. In  FIG. 5B , the desorption mode of operation is illustrated whereby the first port  342  of the capillary sampling array  100  is coupled to the carrier gas source  318  via the port  314  through the flow controller  322 . During the desorption process, the capillary sampling array  100  is rapidly heated from approximately 40° C. to approximately 300° C. by the heater  334 . As the carrier gas flows through the capillary sampling array  100 , any substance collected on the interior walls of each capillary tube  12  ( FIG. 1 ) by the trapping phase is quickly and in a single step released to flow through the port  316  into an analysis column  324 . The analysis column  324  can be, for example, the analysis column of a gas chromatograph.  
         [0031]     In this manner, the capillary sampling array  100  is used to collect samples and quickly release the collected material through a single step sample and desorption process. The thermal desorption process rapidly heats the capillary sampling array  100  (from approximately 40° C. to approximately 300° C. in approximately 20 seconds) to bake off the collected substance contained within the trapping phase on the inside of each capillary tube  10 . As illustrated, the carrier gas is supplied via the carrier gas source  318  in a direction opposite from the direction of flow during the sampling mode of operation.  
         [0032]      FIGS. 6A and 6B  are a schematic diagram collectively illustrating an alternative embodiment of the thermal desorption sampler of  FIGS. 5A and 5B . The thermal desorption sampler  400  includes a valve  402  having a valve body  404  and a rotor  406 . The thermal desorption sampler in  FIGS. 6A and 6B  is referred to as a “ten-port” thermal desorption sampler. The thermal desorption sampler  400  includes a vacuum port  408 , a sampling port  412 , an input port  414  for a stripper column  446 , a vent port  416 , a carrier gas input port  418 , an output port  422 , another output port  424  coupled to an analysis column  458 , and the first port  428  and second port  432  of the capillary array trap  100 .  
         [0033]     During the sampling phase, a vacuum source  438  is coupled through a flow controller  442  to the vacuum port  408 . The vacuum source  438  draws sample air  444  in through the sample port  412 , via the port  432  and into the capillary sampling array  100  in the direction shown.  
         [0034]     Simultaneously, carrier gas is supplied from a carrier gas source  436  through a flow controller  462  through the port  426  and out of the port  424  into the analysis column  458  of a gas chromatograph (not shown). Further, a carrier gas source  454  supplies carrier gas through a flow controller  452  through a carrier gas port  418  and out of the valve  402  via the port  422 . The port  422  is coupled to a conduit  456  and to a stripper column  446 , and then through the port  414  through the valve  402  and out of the port  416  through the vent  448 . The stripper column  446  removes undesirable high boiling point material that otherwise would have flowed to the analysis column  458  after the target compounds have eluted.  
         [0035]     In the six-port thermal desorption sampler  300  all material in the capillary sampling array  100  flows to the gas chromatograph column. This includes many contaminants, such as, for example, vehicle exhaust including materials that range from butane to naphthalene, and organic materials such as terpenes from pine trees, etc. Essentially, these are materials that make detection of the desired materials difficult. Therefore, a stripper column  446  is implemented to remove (i.e., strip) the undesirable high boiling point materials after the desired target compounds have been desorbed and transferred to the analysis column  458 .  
         [0036]      FIG. 6B  is a schematic diagram illustrating the thermal desorption sampler  400  in a desorption mode. The port  408  is coupled through the flow controller  442  to a vacuum source  438  which draws a sample  444  through the port  412 . This maintains a constant flow of sample through the thermal desorption sampler  400 . However, the rotor  406  is rotated such that the port  428  of the capillary array trap  100  is now coupled to port  426  and to a carrier gas supplied through the flow controller  462  from the carrier gas source  436 . The capillary sampling array  100  is rapidly heated, as described above, so that the carrier gas flowing through the capillary sampling array  100  causes any collected substances on the inside walls of the capillary tubes  10  to be desorbed and to flow through the port  414  into the stripper column  446 . The stripper column  446  passes the low boiler target compounds and allows the collected substance to flow through the conduit  464  to the port  422  through the valve  402  and then through the port  424  into the analysis column  458 . It should be mentioned that the analysis column  458  and the stripper column  446  could be portions of the same column, or can be separate columns.  
         [0037]      FIGS. 7A and 7B  are a schematic diagram collectively illustrating another embodiment of the thermal desorption sampler of  FIGS. 5A and 5B . The thermal desorption sampler  500  includes a first valve  502  and a second valve  552 . The first valve  502  operates as a “sample/desorption” valve, as described above, while the second valve  552  directs the output of the capillary sampling array  100  to a stripper column  576  to remove the high boiling point materials from the sample after the desorption operation.  
         [0038]     The first valve  502  include a valve body  504  and a rotor  506 . Both of the valves  502  and  552  in the thermal desorption sampler  500  are “six-port” valves, as described above. The first valve  502  includes a vacuum port  508 , a sample port  512 , a port  514 , a carrier gas port  516 , and a first port  518  and a second port  522  of the capillary array trap  100 .  
         [0039]     During the desorption operation, the first valve  502  is operated to apply a vacuum source  528  to the vacuum port  508  via a flow controller  526 . The vacuum  528  draws in a sample  532  via the sample port  512 . A carrier gas  538  is supplied via the flow controller  536  through the port  516 , and through the first port  518  and then through the capillary array trap  100 . The capillary sampling array  100  is heated by the heater  524  as described above to release collected substances from the trapping phase in the capillary sampling array  100 . The carrier gas carries away any released substances trapped and released by the trapping phase through the ports  522  and  514  into the conduit  534 . The conduit  534  connects the port  514  of the first valve  502  to the port  566  of the second valve  552 .  
         [0040]     The second valve  552 , also referred to as the “stripper valve,” includes a valve body  554 , and a rotor  556 . The second valve  552  also includes a carrier gas port  558 , a vent port  562 , a port  564 , a port  566 , a port  568 , and a port  572 . A carrier gas  586  is supplied through the flow controller  584  into the port  558 , through the valve  552  and then out of the port  562  to the vent  588 . This occurs during the “inject” mode of operation.  
         [0041]     The sample substance transferred from the first valve  502  via conduit  534  passes through the port  566 , through the valve  552  out of the port  564  and via conduit  574  to the stripper column  576 . The stripper column  576  passes low boiling point materials from the collected substance that was just desorbed from the capillary sampling array  100 .  
         [0042]     The output of the stripper column  576  goes through port  568 , through the valve  552  out of the port  572  and into the analysis column  578 , and then to the detector  582 . The detector  582  may be, for example, a gas chromatograph. By “stripping” off high-boiling, late-eluting material from the sample using the stripper column  576 , baseline noise and offset at the detector can be minimized.  
         [0043]     After the inject mode, the second valve  552  is placed in a “strip” mode, whereby the contents of the stripper column  576  are vented via the ports  564  and  562  through the vent  588 . During the strip mode, a carrier gas  586  is supplied through the flow controller  584  into the port  558 , and then out of the port  572 , through the analysis column  578  and into the detector  582 . The second valve  552  (stripper valve) operates independently of the first valve  502 . The second valve  552  is placed in the inject position ( FIG. 7A ) just prior to performing a desorb operation on the contents of the capillary sampling array  100 . After the components of interest have come off the stripper column  576  onto the analysis column  578 , the second valve  552  is rotated to the strip position as shown in  FIG. 7B  so that the unwanted heavy components in the stripper column  576  can be vented.  
         [0044]      FIGS. 8A and 8B  are a schematic diagram collectively illustrating another embodiment of the thermal desorption sampler of  FIGS. 7A and 7B . The thermal desorption sampler  600  includes a first valve  602  and a second valve  652 . The first valve  602  operates as a “sample/desorption” valve, as described above, while the second valve  652  directs the output of the capillary sampling array  100  to a stripper column  676  to remove the low boiling point materials from the sample prior to the desorption operation.  
         [0045]     The first valve  602  includes a valve body  604  and a rotor  606 . Both of the valves  602  and  652  in the thermal desorption sampler  600  are “six-port” valves, as described above. The first valve  602  includes a vacuum port  608 , a sample port  612 , a port  614 , a carrier gas port  616 , and a first port  618  and a second port  622  of the capillary array trap  100 .  
         [0046]     During the desorption operation, the first valve  602  is operated to apply a vacuum source  628  to the vacuum port  608  via a flow controller  624 . The vacuum  628  draws in a sample  632  via the sample port  612 . A carrier gas  638  is supplied via the flow controller  636  through the port  616 , and through the first port  618  and then through the capillary sampling array  100 . The capillary sampling array  100  is heated by the heater  624  as described above to release collected substances from the trapping phase in the capillary sampling array  100 . The carrier gas carries away any released substances trapped and released by the trapping phase through the ports  622  and  614  into the conduit  634 . The conduit  634  connects the port  614  of the first valve  602  to the port  672  of the second valve  652 .  
         [0047]     The second valve  652 , also referred to as the “stripper valve,” includes a valve body  654 , and a rotor  656 . The second valve  652  also includes a carrier gas port  664 , a vent port  666 , a port  668 , a port  672 , a port  662 , and a port  658 . A carrier gas  686  is supplied through the flow controller  684  into the port  664 , through the valve  652  and then out of the port  666  to the vent  688 . This occurs during the “inject” mode of operation.  
         [0048]     The sample substance transferred from the first valve  602  via conduit  634  passes through the port  672 , through the valve  652  out of the port  668  to the stripper column  676 . The stripper column  676  removes any high boiling point materials from the collected substance that was just desorbed from the capillary sampling array  100 .  
         [0049]     The output of the stripper column  676  goes via conduit  674  through port  662 , through the valve  652  out of the port  658  and into the analysis column  678 , and then to the detector  682 . The detector  682  may be, for example, a gas chromatograph detector. By placing the stripper valve  652  in a “strip” mode after the target compounds have passed through the stripper column  676 , heavier, late-eluting compounds can be removed from the head of the stripper column  676  preventing them from carrying over onto the analysis column  678  where they can create noise or increased offset on the detector baseline.  
         [0050]     After the inject mode, the second valve  652  is placed in a “strip” mode, whereby the contents of the stripper column  676  are vented via the ports  668  and  666  through the vent  688 . During the strip mode, a carrier gas  686  is supplied through the flow controller  684  into the port  664 , and then out of the port  662 , through the stripper column  676  and through the port  668 , the valve  652  and through the port  666  to the vent  688 . The output of the port  614  of the first valve  602  is transferred to the conduit  634  and is supplied to the port  672  of the second valve  652 . The contents of the capillary sampling array are then communicated through the second valve  652  through the port  658  and into the analysis column  678 . The second valve  652  (stripper valve) operates independently of the first valve  602 . The second valve  652  is placed in the inject position ( FIG. 8A ) just prior to performing a desorb operation on the contents of the capillary sampling array  100 . After the components of interest have come off the stripper column  676  the valve is placed in the position shown in  FIG. 8B  so that the contents of the capillary sampling array  100  can be transferred to the analysis column  678 , while the unwanted heavy components of the stripper column  676  can be vented.  
         [0051]      FIGS. 9A and 9B  are a schematic diagram collectively illustrating an alternative embodiment of the thermal desorption sampler of  FIGS. 6A and 6B . The thermal desorption sampler  700  includes a valve  702  having a valve body  704  and a rotor  706 . The thermal desorption sampler in  FIGS. 9A and 9B  is referred to as a “ten-port” thermal desorption sampler. The thermal desorption sampler  700  includes a vacuum port  708 , a sampling port  712 , an input port  714  for a stripper column  746 , a vent port  716 , a carrier gas input port  718 , an output port  722 , another output port  724  coupled to an analysis column  758 , and the first port  728  and second port  732  of the capillary array trap  100 .  
         [0052]     During the sampling phase, a vacuum source  738  is coupled through a flow controller  742  to the vacuum port  708 . The vacuum source  738  draws sample air  788  in through the sample port  712 , via the port  732  and into the capillary sampling array  100  in the direction shown.  
         [0053]     Simultaneously, carrier gas is supplied from a carrier gas source  736  through a flow controller  762  through the port  726  and out of the port  724  into the analysis column  758  of a gas chromatograph (not shown). Further, a carrier gas source  754  supplies carrier gas through a flow controller  752  through a carrier gas port  718  and out of the valve  702  via the port  722 . The port  722  is coupled to a conduit  756  and to a stripper column  746 , and then through the port  714  through the valve  702  and out of the port  716  through the vent  748 . The stripper column  746  removes undesirable high boiling point material that may otherwise flow to the analysis column  758 .  
         [0054]      FIG. 9B  is a schematic diagram illustrating the thermal desorption sampler  700  in a desorption/analyze mode. The port  708  is coupled through the flow controller  742  to a vacuum source  738 , which draws a sample  788  through the port  712 . However, the rotor  706  is rotated such that the port  728  of the capillary array trap  100  is now coupled to port  726  and to a carrier gas supplied through the flow controller  762  from the carrier gas source  736 . The capillary sampling array  100  is rapidly heated, as described above, so that the carrier gas flowing through the capillary sampling array  100  causes any collected substances on the inside walls of the capillary tubes  10  to be desorbed and to flow through the port  714  into the stripper column  746 . The stripper column  746  retains the high boiling point material while allowing the target compounds to flow through the conduit  756  to the port  722  through the valve  702  and then through the port  724  into the analysis column  758 . It should be mentioned that the analysis column  758  and the stripper column  746  could be portions of the same column, or can be separate columns.  
         [0055]     The foregoing detailed description has been given for understanding exemplary implementations of the invention in the gas phase only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art without departing from the scope of the appended claims and their equivalents. Other valves can be added to the system for the purpose of isolating certain target compounds for later analysis or for transferring target compounds onto a separate column where they can be separated from the potentially-interfering background matrix on the sample itself. The capillary array trap can also be used to trap target compounds in a liquid matrix by flowing liquid through it for a period of time. A liquid of different polarity can be used to remove the trapped compounds from the trap and transfer them to the head of a liquid chromatography column for the purpose of separating and quantization. Any of the valve arrangements described above can be used to automate this process. The trap can also be desorbed manually by connecting it to the inlet of the chromatograph regardless of the phase used.