Patent Publication Number: US-2020292567-A1

Title: Integrated system for processing vessels containing samples

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application No. 62/818,908 filed on Mar. 15, 2019, the contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to integrated systems for analytical chemistry, and more particularly for processing samples contained in vessels. 
     BACKGROUND OF THE ART 
     Various systems are used in laboratories to process samples received in open vessels, as the processing includes many different steps. The systems are typically spaced-apart and independent from one another. Accordingly, during use, an operator moves the vessels from one independent station to another. 
     Although existing vessel processing systems are satisfactory to a certain degree, there remains room for improvement, especially in reducing the amount of manipulations required by the operator to process the samples satisfactorily. 
     SUMMARY 
     In accordance with a broad aspect, there is provided an integrated system for processing vessels containing samples. The integrated system comprises: a frame; a reagent dispensing station, a sample digestion station, a sample cooling station, a sample normalization station and a sample filtration station within the frame; a vessel manipulation unit having a vessel manipulating member displacing the vessels containing the samples between the reagent dispensing station, the sample digestion station, the sample cooling station, the sample normalization station and the sample filtration station; and a controller communicatively coupled to the vessel manipulation unit, the controller having a processor and a memory having stored thereon instructions which when executed by the processor displace the vessels containing the samples from one station to another. 
     In some embodiments, the instructions are further executable for performing operations on the samples in the vessels, such as digestion, normalization, filtration, reagent dispensing, and cooling. 
     Features of the systems, devices, and methods described herein may be used in various combinations, in accordance with the embodiments described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the accompanying figures in which: 
         FIG. 1  is a block diagram of an example of an integrated system for processing vessels, in accordance with one or more embodiments; 
         FIG. 2  is a perspective view of another example of an integrated system for processing vessels, in accordance with one or more embodiments; 
         FIG. 3  is a perspective view of vessels held together by a vessel holder, for use with an integrated system, in accordance with one or more embodiments; 
         FIG. 4  is a view of a vessel, in accordance with one or more embodiments; 
         FIG. 5  is a view of a vessel manipulation member, in accordance with one or more embodiments; 
         FIG. 6  is a view of an integrated system with the vessels in a vessel holder held by the vessel manipulation member of  FIG. 5 , in accordance with one or more embodiments; 
         FIG. 7  is a sectional view of the integrated system of  FIG. 2 , taken at line  7 - 7 , in accordance with one or more embodiments; 
         FIG. 8  is a view of an integrated system with the vessels at a sample digestion station, in accordance with one or more embodiments; 
         FIG. 9A  is a top perspective view of an evaporation stopper plate, in accordance with one or more embodiments; 
         FIG. 9B  is a bottom perspective view of an evaporation stopper plate, in accordance with one or more embodiments; 
         FIG. 10  is a view of an integrated system with vessels at a reagent dispensing station, at a sample cooling station and at a sample normalization station, in accordance with one or more embodiments; 
         FIG. 11  is an exploded view of an example of a filtering system of the sample filtration station of an integrated system, in accordance with one or more embodiments; 
         FIG. 12  is a view of an integrated system showing the vessels at a sample filtration station, in accordance with one or more embodiments; 
         FIG. 13  is a sectional view of the integrated system of  FIG. 2 , taken at line  13 - 13 , in accordance with one or more embodiments; and 
         FIGS. 14A and 14B  show an example of a fluid blower of the ventilation unit, in accordance with one or more embodiments. 
     
    
    
     It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
     DETAILED DESCRIPTION 
       FIG. 1  shows an example of an integrated system  100  for processing vessels containing samples, in accordance with one or more embodiments. The integrated system  100  may be used to reduce the amount of manipulations required by operates in order to process samples and/or reduce the amount of samples needed to reach a given objective, i.e. perform reliable element analysis contained in the sample. 
     In some embodiments, the vessels can be vessels for small volumes, such as but not limited to 2 mL, 5 mL, 12 mL, 15 mL, and the like. As depicted, the integrated system  100  can have a frame  102  within which are provided a reagent dispensing station  104 , a sample digestion station  106 , a sample cooling station  108 , a sample normalization station  110  and a sample filtration station  112 . 
     The reagent dispensing station  104  can be used to receive the vessels and to dispense reagent inside each one of the vessels so that the reagent can react with the samples contained therein. An example type of reagent can include corrosive acid(s) and the like. Any other suitable reagent can be considered. 
     In some embodiments, the reagent dispensing station  104  can be configured to mix the dispensed reagent within the samples inside the vessels. For instance, the reagent dispensing station  104  can shake the vessels for a predetermined period of time in order to mix the dispensed reagent within the samples in a satisfactory manner. In some other embodiments, the samples can be mixed using a magnetic stirrer, a bubble stirring mechanism and any other mixing techniques. 
     The volume and/or the type of dispensed reagent can be the same for all vessels. However, in some other embodiments, the volume and/or the type of dispensed reagent can be different for each one, or a subset, of the vessels. For instance, the volume and/or the type of dispensed reagent can be a function of the remaining volume and/or of the type of sample inside each one of the vessels. Other implementations may also apply. 
     The sample digestion station  106  can be used to digest the samples contained inside each one of the vessels. An example type of digestion can require heating the vessels. Another example type of digestion can require radiating microwave and/or infrared radiation across each of the vessels. Another type of digestion can involve both heating the vessels and radiating the vessels with a given type of radiation. In these embodiments, digestion conditions can include, but are not limited to, a given temperature at which the vessels are heated, a rate at which the temperature is raised, a given period of time during which the vessels are heated/radiated, a given spectral content of the radiation and/or a given power of the radiation, and the like. 
     The digestion type and/or the digestion conditions can depend on the application. For instance, in some embodiments, the digestion type and/or digestion conditions can be suited for trace metal digestion, cyanide determination, digestion for chemical oxygen demand, and the like. Other implementations may apply. 
     The sample cooling station  108  can be used to cool the samples contained inside each one of the vessels. The cooling can be passive or active depending on the embodiment. For instance, the vessels can be passively cooled by letting them interact with surrounding air, by which the temperature of the samples can tend towards the ambient temperature. In other embodiments, the vessels can be actively cooled by blowing surrounding air towards the vessels, which can increase a cooling rate at which the vessels tend to the ambient temperature. In other embodiments, the vessels can be actively cooled by sucking away hot air from the vessels, which can increase a cooling rate at which the vessels tend towards an ambient temperature. In alternate embodiments, the vessels can be actively cooled by blowing cold pressure air towards the vessels and/or by cooling the vessels via a thermoelectric cooling element involving the thermoelectric Peltier effect, which may cool the vessels to a temperature below the ambient temperature, if desired. The sample cooling station  108  can be configured to maintain the vessels at a desired temperature for a given period of time once they have reached the desired temperature. 
     The cooling type and/or the cooling conditions can vary from one embodiment to another. For instance, it can be desirable to cool the vessels rapidly in some embodiments whereas the cooling rate of the vessels is insignificant in other embodiments. 
     The sample normalization station  110  can be used to determine remaining volumes V r  of the samples inside each of the vessels and to normalize the volumes of the samples to a predetermined normalized level V n . The normalization step can be performed by adding a given volume V a  of a normalization fluid inside each of the vessels corresponding to the predetermined normalized level V n  minus the remaining volume V n  as measured (V a =V n −V r ). Example types of normalization fluid can include, but are not limited to, deionized water, distilled water, internal standard, and the like. In some embodiments, all the vessels can be normalized simultaneously whereas in other embodiments, the vessels can be normalized sequentially or by subset. 
     The sample filtration station  112  can be used to filter the samples of the vessels. For instance, the processing steps such as the reagent dispensing, digestion, cooling and normalization steps can cause solids to form inside the vessels. The samples can be filtered into a solid part and a fluid part. The fluid part can be provided in corresponding recipient vessels, thereby allowing other processing steps to be carried out independently on either one or both of the solid and fluid parts of the filtered samples. The sample filtration station  112  can be configured to perform the filtering of the samples on an individual and independent basis, to avoid any possible contamination between the samples. Examples of filtration types can include, but are not limited to, gravity filtration, vacuum filtration, cold filtration, hot filtration, decantation and/or separation. Other types of filtration can be considered. The sample filtration station  112  can also be configured to perform filtering of all the samples simultaneously. 
     The integrated system  100  can have a vessel manipulation unit  116  with a vessel manipulating member  114  moving between the reagent dispensing station  104 , the sample digestion station  106 , the sample cooling station  108 , the sample normalization station  110  and the sample filtration station  112 . 
     In some embodiments, the vessel manipulation member  114  can have one or more vessel engaging features which can engage the vessels, directly or indirectly, in order to move them from one station to another, collectively or individually. Examples of such engaging features can include, but are not limited to, one or more pushing members, one or more pulling members, one or more gripping members, one or more lifting platforms, one or more hook and loop features, one or more groove and tongue features, and/or any other suitable engaging arrangements. In some embodiments, the vessel engaging features can be provided at an end of a robotized arm. In these embodiments, the robotized arm can be articulated to move freely in up to six degrees of freedom, for instance. Other vessel manipulation members can also be considered. For instance, one or more conveyors can be used to move the vessels from one station to another. 
     A controller  118  is provided to control the vessel manipulation unit  116  to move the vessel manipulation member  114  from one station to another. In some embodiments, the controller  118  can be configured to operate one or more of the reagent dispensing station  104 , the sample digestion station  106 , the sample cooling station  108 , the sample normalization station  110  and the sample filtration station  112 . 
     The controller  118  can be communicatively coupled to the vessel manipulation unit  116  via a wired connection. However, in some other embodiments, the controller  118  can be communicatively coupled to the vessel manipulation unit  116  via a wireless connection, or a combination of both a wired connection and a wireless connection. 
     As depicted, the controller  118  can have a processor  120  and a memory  122  having stored thereon instructions  124  which when executed by the processor  120  perform steps of moving the vessel manipulating member  114  from one station to another to process vessels at the station where they are moved, and/or perform operations on the samples inside the vessels, e.g. adding agent, digestion, normalization, etc. 
     The processor  120  may comprise any suitable devices configured to implement the steps described herein such that instructions  124 , when executed by the controller  118  or other programmable apparatus, may cause the functions/acts/steps performed to be executed. The processor  120  may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), a graphical processing unit (GPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof. 
     The memory  122  may comprise any suitable known or other machine-readable storage medium. The memory  122  may comprise non-transitory computer readable storage medium, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory  122  may include a suitable combination of any type of computer memory that is located either internally or externally to the controller, for example random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory  122  may comprise any storage means (e.g., devices) suitable for retrievably storing machine-readable instructions  124  executable by processor  120 . 
     Depending on the embodiment, the controller  118  can be communicatively coupled, via a wired and/or wireless connection, to one or more of the reagent dispensing station  104 , the sample digestion station  106 , the sample cooling station  108 , the sample normalization station  110  and the sample filtration station  112 , for controlling thereof, examples of which are described below. 
       FIG. 2  shows another example of an integrated system  200 . As depicted, the integrated system  200  can have a frame  202  to which are made integral a reagent dispensing station  204 , a sample digestion station  206 , a sample cooling station  208 , a sample normalization station  210  and a sample filtration station  212 . 
     In the illustrated example, the reagent dispensing station  204 , the sample cooling station  208  and the sample normalization station  210  share a first vessel receiving region  224  on a top surface  222  of the frame  202 . The sample digestion station  206  is at a second vessel receiving region  236  on the top surface  222  of the frame  202 . As shown, the first region  224  can be spaced-apart from the second region  236 , which can avoid any potential risk (e.g., dropping reagent on a heating element). In alternate embodiments, each of the reagent dispensing station  204 , the sample digestion station  206 , the sample cooling station  208 , the sample normalization station  210  and the sample filtration station  212  can have its own region on the top surface  222  of the frame  202 , if desired. 
     In this example, the frame is provided in the form of a housing inside which are enclosed parts of the integrated system. For instance, the integrated system can have a controller  218  enclosed within the housing. 
     In this specific example, the controller  218  is communicatively coupled to the vessel manipulation unit  216 , the reagent dispensing station  204 , the sample digestion station  206 , the sample cooling station  208 , the sample normalization station  210  and the sample filtration station  212 . The controller  218  can also be communicatively coupled to a ventilation unit  220 , which will be described below in detail. 
     Similarly to the integrated system  100  of  FIG. 1 , the integrated system  200  of  FIG. 2  can have a vessel manipulation unit  216  with a vessel manipulating member  214  displaceable between the reagent dispensing station  204 , the sample digestion station  206 , the sample cooling station  208 , the sample normalization station  210  and the sample filtration station  212 . 
     In this specific embodiment, the integrated system  200  can have a washing station  226  and one or more reagents reservoirs  228  recessed from the top surface  222  of the frame  202 . The sample filtration station  212  may comprise a filtering system  10  and a vessel pressing plate  232 , which will be explained in more detail below. 
       FIG. 3  shows an example of vessels  302  that can be processed using an integrated system, such as the integrated systems  100 ,  200  of  FIGS. 1 and 2 . As illustrated, the vessels  302  are held together by a vessel holder  300 . In this example, the vessel holder  300  can have vessel apertures receiving corresponding vessels  302  therein. 
     As shown, the vessels  302  are provided in an array  304  of  24  vessels. However, in some embodiments, arrays of 12, 48 or 96 samples are also possible. Other sizes of arrays are also considered. Each vessel  302  may be sized and shaped to receive about 2 mL sample, as best shown in  FIG. 4 . In some embodiments, the vessels  302  can be designed for small volumes, for example, 2 to 12 mL. in some other embodiments. Other volumes are also considered. In the illustrated embodiment, the vessel  302  has a pierceable end  404  and an opposite, open end  402  for receiving a sample  406 . 
     In some embodiments, the vessels  302  are consumables. Accordingly, the vessels  302  may be compatible with injection moulding processes in order to produce the plates in an easy and affordable manner. The vessel holder  300  can be consumable, too, in some embodiments. 
     Moreover, in some embodiments, the vessels  302  and the vessel holder  300  are made of materials which are compatible with chemicals while being resistant to high temperatures generally experienced in conventional processes. For instance, in some embodiments, the vessels  302  and the vessel holder  300  are acid resistant and resist to up to 200° C. 
     As illustrated, each vessel  302  can have a tapered shape  408  so as to be matingly engageable into a corresponding one of the vessel apertures of the vessel holder  300 . The vessels  302  may be held together via the vessel holder  300 , which can facilitate the manipulation of the vessel manipulating member  214  an enlarged view of which is shown in  FIG. 5 . 
     As depicted, the vessel manipulating member  214  can have two fingers  502  substantially parallel and spaced-apart from one another. In some embodiments, the fingers  502  can be parallel to a plane of the top surface  222  of the frame  202 . The two fingers  502  are movable between a gripping position, in which the two fingers  502  are brought towards one another, and a release position, in which the two fingers  502  are spaced away from one another, or vice versa. 
     Other embodiments are also considered for the vessel manipulating member  214 . For instance, the vessel manipulating member  214  can have more than two fingers  502 , a single finger or no finger at all depending on the embodiment. In some embodiments, the vessel manipulating member  214  can be provided in the form of a robotized arm, a conveyor, and/or any rack engaging device suitable for displacing the vessels  302  and/or the vessel holder  300  from one station to another. 
     During use, the fingers  502  can grip the vessel holder  300  while in the gripping position and release the vessel holder  300  while in the release position. The fingers  502  may alternatively grip the vessels  302  directly instead of the vessel holder  300 . Each finger can have a portion with gripping material  504 , to enhance the grip on the vessel holder  300  and/or on the vessels  302 . 
     Turning now to  FIG. 6 , the fingers  502  are shown in the gripping position holding the vessel holder  300 , and transporting the vessels  302 . As depicted in this example, the vessel manipulating member  214  is displacing the vessels  302  towards the reagent dispensing station  204 . 
     In the illustrated embodiment, the reagent dispensing station  204  can be recessed from the top surface  222  of the frame  202  at the first vessel receiving region  224 . The reagent dispensing station  204  can have a vessel receiving plate  612  received in the first vessel receiving region  224 . The vessel receiving plate  612  can have first vessel apertures  610  which are spaced-apart from one another for receiving corresponding ones of the vessels  302 . 
     In some embodiments, the reagent dispensing station  204  can have one or more integrated reservoirs  606  (hereinafter “the integrated reservoir”) within the frame  202 . The integrated reservoir  606  can be used to contain one or more reagents for use by the reagent dispensing station  204 . The integrated reservoir  606  can have a base  616 , a top  622 , walls  620  spacing the base  616  from the top  622  in a sealed manner, and one or more openings  626  through which reagent can be pumped or otherwise removed. In some embodiments, the integrated reservoir  606  can be partially or wholly enclosed within the housing. The integrated reservoir  606  can be closed or open to the surrounding environment. The integrated reservoir  606  can be acid-resistant in some embodiments. 
     The reagent dispensing station  204  can have one or more pumping assemblies  602  (hereinafter “the reagent pumping assembly”) which can be used to pump reagent from the integrated reservoir  606  in order to dispense the pumped reagent into the vessels  302 . 
     In some embodiments, the reagent pumping assembly  602  can have one or more reagent conduits  604  (hereinafter “the reagent conduit”) in fluid communication with the integrated reservoir  606 . The reagent conduit  604  can have a drawing end  618  within the integrated reservoir  606  via the opening  626  and an opposite, dispensing end  615  at the reagent dispensing station  204 . The reagent conduit  604  can be provided in the form of a tube, a hose, a pipe and the like. In some embodiments, the reagent conduit  604  can be acid-resistant. The reagent conduit  604  can also be flexible. The reagent conduit  604  can have a length which allows its dispensing end  615  to extend across any position of the reagent dispensing station  204 . Alternatively to having the integrated reservoir  606  or in combination therewith, external reservoirs  699  separate from the integrated system  200  may be used. Such external reservoirs  699  may store large volumes of reagents which may be added to the vessel by dispensing via the reagent dispensing station  204 . Such external reservoirs  699  may also contain normalization liquid. In some embodiments, the drawing end  618  of the reagent conduit  604  may be connected to the external reservoirs  699  through a pump  698 , such as a syringe pump used to dispense reagents or perform normalization. 
     The reagent pumping assembly  602  can have one or more pumps  624  (hereinafter “the reagent pump”) in fluid communication with the reagent conduit  604  to actively pump reagent from the drawing end  618  of the reagent conduit  604  towards the dispensing end  615  of the reagent conduit  604 . The reagent pump  624  can be a positive displacement pump, an impulse pump, a syringe pump, a velocity pump, a gravity pump, a peristaltic pump, a valve-less pump and/or any other suitable type of reagent pump. The drawing end  618  and the dispensing end  615  of the reagent conduit  604  can be the same end of the reagent conduit  604  in some embodiments. 
     In some embodiments, one or more dispensing pumps  614  are provided for the washing station  226 . One of the dispensing pumps  614  may be for pumping a cleaning agent (such as water) to the washing station  226  from a reservoir of the cleaning agent. Another of the dispensing pumps  614  may be for pumping waste cleaning agent from the washing station  226  to a waste collector container. The dispensing pumps  614  may be fluidly connected to the cleaning agent reservoir, the washing station  226 , and the waste collector container via tubes. 
     In some embodiments, the dispensing end  615  of the reagent conduit  604  can be movable at the reagent dispensing station  204 . More specifically, the dispensing end  615  of the reagent conduit  604  can be sequentially moved to a plurality of vessel positions within the reagent dispensing station  604 . 
     In some embodiments, the dispensing end  615  of the reagent conduit  604  can be moved using the vessel manipulation unit  216 . In some embodiments, the dispensing end  615  of the reagent conduit  604  can be moved using another, separate and independent conduit manipulation unit dedicated to the displacement of the reagent conduit  604 . In such embodiments, the vessel manipulation unit  216  can be operated to first move the vessels  302  to a first vessel position within the reagent dispensing station  204 , and the conduit manipulation unit can move the dispensing end  615  of the reagent conduit  604  towards in-position vessels, whereby the reagent can be dispensed inside each of the vessels  302  upon activation of the reagent pumping assembly  602 . 
     Accordingly, the reagent dispensing station  204  can be operated in accordance with instructions stored on the memory of the controller  218 . The dispensing of reagent into the vessels  302  can be performed sequentially, simultaneously, or a combination thereof, depending on the embodiment and on the number of reagent conduits  604 , for instance. 
     In some embodiments, the reagent conduit  604  first moves to the integrated reservoir  606 , dips into the integrated reservoir  606 , sucks some reagent, moves to the vessel  302 , dips into the vessel  302 , dispenses the reagent, and so forth, according to preprogrammed instructions stored on the memory of the controller  218 . This can be referred to as a pick and place process. More than one reagent conduit  604  can be equipped to the integrated system  200  for dispensing more than one reagent in order to avoid any cross contamination. The washing station  226  has a first reservoir  608  on the top surface  222  of the integrated system  200 . The other two reservoirs  228  proximate to the washing reservoir  608  can be reagent reservoirs used in the reagent dispensing step performed by the reagent dispensing station  204 . During use, dispensing ends and/or bubble stirring tips can be washed at the washing station  226  after they come out from a sample, or before dipping to a reagent reservoir. 
     As shown in  FIG. 7 , the sample digestion station  206  can be recessed from the top surface  222  of the frame  202 . As shown, the sample digestion station  206  is recessed at the second vessel receiving region  236  which is spaced-apart from the first vessel receiving region  224 . 
     In some embodiments, the sample digestion station  206  can have one or more heating elements  702  (hereinafter “the heating element”) received in the second vessel receiving region  236 . The heating element  702  can be provided in the form of one or more resistive conductor(s), one or more thermoelectric element(s), one or more infrared radiation source(s), one or more microwave radiation source(s) and the like. Other types of heating elements  702  can be considered. The heating element  702  can be distributed to uniformly or selectively heat the vessels  302  during use. 
     The sample digestion station  206  can also have a thermally conductive block  704  which is received in the second vessel receiving region  236 . In some embodiments, the thermally conductive block  704  is thermally connected to the heating element  702 . The thermally conductive block  704  can be provided in the form of a block of thermally conductive material such as graphite, aluminum, steel or any other metal. In some embodiments, the thermally conductive block  704  can be configured to uniformly distribute heat across the block, which can in turn heat the vessels  302  uniformly. The thermally conductive block  704  can have second vessel apertures  706  spaced-apart from one another to receive the vessels  302  during digestion. 
     The heating element can be activated by the controller  218  to heat the thermally conductive block  704  to high temperatures including, but not limited to, 200° C. In some embodiments, the heating element  702  can be activated by a switch or button of the integrated system  200 , or otherwise be remotely activated. 
     Accordingly, the sample digestion station  206  can be operated in accordance with instructions stored on the memory of the controller  218 . The heating of the vessels  302  can be performed sequentially, simultaneously, or a combination thereof, depending on the embodiment and on the number of independent heating elements  702 , for instance. 
       FIG. 8  shows the vessels  302  at the sample digestion station  206 . During digestion of the samples, the samples can evaporate and thus lead to sample losses and/or undesirable fumes. Accordingly, in some embodiments, the sample digestion station  206  can have an evaporation stopper plate  802  which is movable between a digestion position, in which the evaporation stopper plate  802  is above the second vessel receiving region  236 , and a rest position, in which the evaporation stopper plate  802  rests away from the second vessel receiving region  236 , such as shown in  FIG. 8 . 
       FIGS. 9A and 9B  show top and bottom views of an example of the evaporation stopper plate  802 . As depicted, the evaporation stopper plate  802  is sized and shaped to be received on the vessels  302 . More specifically, in this example, the evaporation stopper plate  802  can be sealingly received on open surfaces of the vessels  302 . In the digestion position, the evaporation stopper plate  802  can prevent evaporation from leaving the vessels  302  and can help the evaporation to condense on a portion of an undersurface of the evaporation stopper plate  802 , thereby favoring the condensed fluid to drip back into the sample, and so forth, until the digestion is completed. 
     In some embodiments, the evaporation stopper plate  802  can have an array of bulges  902  protruding from the undersurface  904  of the evaporation stopper plate  802 , such as shown in  FIG. 9B . The evaporation stopper plate  802  is similar in size and shape to the vessel holder  300 , such that vessels  302  in the vessel holder  300  are aligned with the bulges  902  in the evaporation stopper plate  802 . When the evaporation stopper plate  802  is received in the digestion position, the bulges  902  can partially protrude within the vessels  302 . In this way, the fluid that is condensed on the bulge  902  can tend to flow in a laminar fashion inwardly towards a center of the bulge  902 , at which point drops may form. The drops so-formed may drip back into the sample, until the digestion is completed. 
     Movement of the evaporation stopper plate  802  can be operated in accordance with instructions stored on the memory of the controller  218 . More than one evaporation stopper plate  802  can be considered in some embodiments. The evaporation stopper plate  802  can be moved by the vessel manipulating member  214  in some embodiments. 
       FIG. 10  shows the vessels  302  at the sample cooling station  208 . As depicted, the sample cooling station  208  is recessed from the top surface  222  of the frame  202  at the first vessel receiving region  224 . 
     The sample cooling station  208  can have the vessel receiving plate  612  received in the first vessel receiving region  224  (as best shown in  FIG. 8 ). As described above, the vessel receiving plate  612  can have first vessel apertures  610  which are spaced-apart from one another for receiving corresponding ones of the vessels  302 . 
     The sample cooling station  208  can be used to cool the samples contained inside each one of the vessels  302 . As mentioned above, the cooling can be passive or active depending on the embodiment. In the illustrated embodiment, the vessels  302  can either be passively cooled by letting them interact with surrounding air, by which the temperature of the samples can tend towards the ambient temperature, or by blowing air towards (or sucking hot air away from) the vessels using a ventilation unit  220 . An example of the ventilation unit  220  will be described below. In some embodiments, a gap  1004  may be provided between the vessels  302  and the first vessel receiving region  224  so as to encourage convection to occur around the vessel  302 , thereby exchanging heat with the surrounding environment. 
     Accordingly, the sample cooling station  208  can be operated in accordance with instructions stored on the memory of the controller  218 . The cooling of the vessels  302  can be performed sequentially, simultaneously, or a combination thereof, depending on the embodiment and on the number of independent thermoelectric elements, if any. For instance, the controller  218  can have instructions to maintain the vessels  302  cool at the sample cooling station  208  for a given period of time, which can depend on the digestion conditions with which digestion has been performed at the sample digestion station  206 . In some embodiments, the cooling can last as long as a given temperature is reached, as can be measured by a temperature sensor  1006  installed in the recessed region of the sample cooling station  208 . 
     Also shown in  FIG. 10 , the vessels  302  are at the sample normalization station  210 . The sample normalization station  210  can share a location of the reagent dispensing station  204  and of the sample cooling station  208 . In some embodiments, the sample normalization station  210  can have one or more normalization fluid reservoirs  1014  (hereinafter “the normalization fluid reservoir”) within the frame  202 . The normalization fluid reservoir  1014  can be used to contain one or more normalization fluids (hereinafter “the normalization fluid”) for use by the sample normalization station  210 . The normalization fluid reservoir  1014  can have a base  1018 , a top  1016 , walls  1020  spacing the base  1018  from the top  1016  in a sealed manner, and one or more openings  1024  (hereinafter “the normalization fluid opening”) through which normalization fluid can be pumped or otherwise removed. In some embodiments, the normalization fluid reservoir  1014  can be partially or wholly enclosed within the housing. The normalization fluid reservoir  1014  can be acid-resistant in some embodiments. The normalization fluid reservoir  1014  can be integrated into the integrated system  200  in some embodiments. In some other embodiments, the normalization fluid reservoir  1014  can be provided in the form of a standalone reservoir lying outside the integrated system  200  but in fluid communication to the reagent conduit  604  through tubing and pumping, for instance. 
     The sample normalization station  210  can have one or more pumping assemblies  1026  (hereinafter “the normalization fluid pumping assembly”) which can be used to pump normalization fluid from the normalization reservoir  1014  in order to dispense the pumped normalization fluid into the vessels  302 . 
     In some embodiments, the normalization fluid pumping assembly  1026  can have one or more normalization fluid conduits  1028  (hereinafter “the normalization fluid conduit”) in fluid communication with the normalization fluid reservoir  1014 . The normalization fluid conduit  1028  can have a drawing end  1012  within the normalization fluid reservoir  1014  via the normalization fluid opening  1024  and an opposite, dispensing end  1008  at the sample normalization station  210 . The normalization fluid conduits  1028  can be provided in the form of a tube, a hose, a pipe and the like. In some embodiments, the normalization fluid conduit  1028  can be acid-resistant. The normalization fluid conduit  1028  can also be flexible. The normalization fluid conduit  1028  can have a length which allows its dispensing end  1008  to extend across any position of the sample normalization station  210 . 
     The normalization fluid pumping assembly  1026  can have one or more pumps  1022  (hereinafter “the normalization fluid pump”) in fluid communication with the normalization fluid conduit  1028  to actively pump normalization fluid from the drawing end  1012  of the normalization fluid conduit  1028  towards the dispensing end  1008  of the normalization fluid conduit  1028 . The normalization fluid pump  1022  can be a positive displacement pump, an impulse pump, a syringe pump, a velocity pump, a gravity pump, a peristaltic pump, a valve-less pump and/or any other suitable type of pump. 
     In some embodiments, the dispensing end  1008  of the normalization fluid conduit  1028  can be movable within the sample normalization station  210 . More specifically, the dispensing end  1008  of the normalization fluid conduit  1028  can be sequentially moved to a plurality of vessel positions within the sample normalization station  210 . 
     In some embodiments, the dispensing end  1008  of the normalization fluid conduit  1028  can be moved using the vessel manipulation unit  216 . In some embodiments, the dispensing end  1008  of the normalization fluid conduit  1028  can be moved using another, separate and independent conduit manipulation unit dedicated to the moving of the normalization fluid conduit  1028 . In such embodiments, the vessel manipulation unit  216  can be operated to first move the vessels  302  to a second vessel position within the sample normalization station  210 , and then the conduit manipulation unit can move the dispensing end  1008  of the normalization fluid conduit  1028  towards the in-position vessels  302 , whereby the normalization fluid can be dispensed inside each of the vessels  302  upon activation of the normalization fluid pumping assembly  1026 . 
     Accordingly, the sample normalization station  210  can be operated in accordance with instructions stored on the memory of the controller  218 . The dispensing of normalization fluid into the vessels  302  can be performed sequentially, simultaneously, or a combination thereof, depending on the embodiment and on the number of normalization fluid conduits  1028 , for instance. 
     As mentioned above, the sample normalization station  210  can be configured to determine remaining volumes V r  of the samples inside each of the vessels  302  and to normalize the volumes of the samples to a predetermined normalized level V n , i.e., by dispensing a given volume V a  of a normalization fluid inside each of the vessels  302  corresponding to the predetermined normalized level V n  minus the remaining volume V r  as measured (V a =V n −V r ). 
     The remaining volumes V r  can be measured using one or more level sensors  1010  (hereinafter “the level sensor”) of the sample normalization station  210 . The level sensor  1010  can be a point level sensor and/or a continuous level sensor. Examples of such level sensors  1010  can include, but are not limited to, optical level sensor(s), laser level sensor(s), ultrasonic level sensor(s), capacitance level sensor(s), hydrostatic pressure level sensor(s) and the like. 
     In some embodiments, the level sensor  1010  can be moved using the vessel manipulation unit  216 . In some embodiments, the level sensor  1010  can be moved using another, separate and independent sensor manipulation unit dedicated to the moving of the level sensor. In such embodiments, the vessel manipulation unit  216  can be operated to move the vessels  302  to the sample normalization station  210 , and then the sensor manipulation unit can move the level sensor towards the in-position vessels, whereby the remaining volume V r  inside each of the vessels  302  can be measured. 
     Accordingly, when the vessels  302  are moved to the sample normalization station  210 , the normalization fluid pumping assembly  1026  can add normalization fluid inside each one of the vessels  302  in accordance with instructions stored on the memory of the controller  218  based on the measured remaining volumes V r . The predetermined normalized level V n  can be stored on the memory of the controller  218  or be received from a remote network. 
     Still referring to  FIG. 10 , the sample filtration station  212  may be recessed from the top surface  222  of the frame  202  to define a third vessel receiving region  1002 . In this specific embodiment, the sample filtration station  212  can have a removable filtering system  10  received in the third vessel receiving region  1002 . As shown, the sample filtration station  212  can have recipients vessels  58  on which is received the removable filtering system  10 . 
       FIG. 11  shows an example of the filtering system  10 . As depicted, the filtering system  10  can have a vacuuming plate  18  with a base  20 , walls  22  extending from the base  20  to define a cavity  24 , and a vacuum port  26  in fluid communication with the cavity  24 . In some embodiments, the vacuum port  26  is used to pull air from the cavity  24 . The base  20  can have outlet openings  28  which are spaced-apart from one another in this example. 
     As illustrated, the filtering system  10  can have a filtering unit  30  which is removably mounted to the vacuuming plate  18  and which encloses the cavity  24  when so-mounted. The filtering unit  30  can have a filter plate  32  with filter openings  34  aligned with the outlet openings  28  of the vacuuming plate  18  to allow fluid flow therebetween. 
     The filtering unit  30  can have a filtering membrane  36  which covers the filter openings  34  of the filter plate  32 . The filtering membrane  36  is adapted to prevent a solid portion of the sample from passing through the filtering membrane  36  while allowing a fluid portion of the sample to flow through the filtering membrane  36 . The fluid portion of the sample is also referred to as the “filtered sample” in this disclosure. 
     As depicted, the filtering unit  30  can also have a piercing plate  38  which is removably received on the filter plate  32  and which sandwiches the filtering membrane  36  between the filter and piercing plates  32  and  38 . As such, the filtering membrane  36  lies in a plane  40  extending between top and bottom surfaces  42  and  44  of the filtering unit  30  in this example. As shown, the piercing plate  38  can have vessel piercing members  46  which extend away from the filtering membrane  36 . Each vessel piercing member  46  can have a respective conduit  48  extending through the piercing plate  38  and aligned with a corresponding one of the filter openings  34  of the filter plate  32  to allow fluid flow therebetween. 
     Accordingly, when the filtering unit  30  is mounted to the vacuuming plate  18 , the conduits  48  of the vessel piercing members  46  of the piercing plate  38 , the filter openings  34  of the filter plate  32  and the outlet openings  28  of the vacuuming plate  18  are aligned with one another. Such an alignment defines fluid flow paths  50  extending through the conduits  48 , through corresponding portions of the same filtering membrane  36 , through the filter openings  34  and through the outlet openings  28  of the vacuuming plate  18 . The outlet openings  28  of the vacuuming plate  18  are aligned with the recipients vessels  58  to allow fluid communication therebetween. 
     Accordingly, upon vacuum, the sample as filtered through the membrane  36  is received in a corresponding recipient vessel  58  located below the vacuuming plate  18  and aligned with the outlet openings  28  to allow fluid flow therethrough, after which the filtered sample  12  can be collected for subsequent uses. 
     An example of the filtering system  10  is thoroughly described in U.S. Provisional Patent Application Ser. No. 62/818,837, the content of which is hereby incorporated by reference. Other examples of filtration systems  10  can be considered, as seen fit for one or more other applications. 
       FIG. 12  shows the vessels  302  at the sample filtration station  212 . As shown, the integrated system  200  can have a vessel pressing plate  232  movable between a pressing position, in which the vessel pressing plate  232  is brought towards the filtering system  10 , and a rest position, in which the vessel pressing plate  232  rests away from the filtering system  10 . 
     When the vessels  302  are received on the filtering system  10 , the vessel pressing plate  232  can be moved to the pressing position and thereby apply a pressure on the vessels  302  which in turn causes them to be pierced by corresponding ones of the vessel piercing members  46  of the piercing plate  38 . In this specific embodiment, the filtering process is initiated by moving the vessels  302  onto the filtering system  10  and then by moving the vessel pressing plate  232  into the pressing position. 
     In some embodiments, the vessel pressing plate  232  can be moved using the vessel manipulation unit  216 . In some embodiments, the vessel pressing plate  232  can be moved using another, separate and independent pressing plate displacement unit dedicated to the displacement of the vessel pressing plate  232 . The pressing plate displacement unit is configured to force the vessels  302  against the piercing plate of the filtering system  10  with sufficient strength in order that the vessels  302  be pierced by corresponding ones of the vessel piercing members  46 . In such embodiments, the pressing plate displacement unit can be operated by the controller  218  to first displace the vessel pressing plate  232  between the pressing position and the rest position. 
       FIG. 13  shows an example of a ventilation unit  220  of the integrated system  200 . As depicted, the ventilation unit  220  can have one or more ventilation conduits  1304 ,  1306  extending between at least one of the stations  204 ,  206 ,  208 ,  210 ,  212  and an exhaust port  1302  extending through the frame  202 . The ventilation conduits  1304 ,  1306  can be wholly or partially housed within the housing of the integrated system  200 . The number of ventilation conduits  1304 ,  1306  can depend on the implementation. 
     In the illustrated embodiments, the ventilation conduits  1304 ,  1306  can have first ventilation conduits  1304  extending between the sample cooling station  208  and the exhaust port  1302 . Second ventilation conduits  1306  extending between the sample digestion station  206  and the exhaust port  1302  can also be provided. A hose may be installed to guide the fumes from the exhaust port  1302  to outdoors. 
     In some embodiments, the first and second ventilation conduits  1304 ,  1306  extend between a respective one of the first and second vessel receiving regions  224 ,  236  and the exhaust port  1302 . More specifically, the ventilation conduits  1304 ,  1306  can extend from the recessed regions of the sample digestion and cooling stations  206 ,  208 . 
     In this way, undesirable fumes that exit from the vessels  302 , whenever they are at the sample digestion station  206  or sample cooling station  208 , can be drawn under the top surface  222  of the frame  202  towards the exhaust port  1302 . Using such a ventilation unit  220  may reduce the need for a hood fume, which can be inconvenient at least in terms of cost, footprint and obstructiveness in a laboratory environment. Such ventilation may prevent fumes from corroding the Z and Y axes of the instrument(s). The ventilation may also serve as a cooling means by drawing away hot air around the vessels. 
     The ventilation unit  220  can have a cavity  1308  in fluid communication with the ventilation conduits  1304 ,  1306 . The cavity  1308  can be sized and shaped to receive a fluid blower blowing fluid in or out of one or more of the stations, from or towards the exhaust port  1302 .  FIGS. 14A and 14B  show an example of the fluid blower, which is in this case provided in the form of a blower fan  1402 . However, in some other embodiments, other types of fluid blower can be considered. For instance, in alternate embodiments, the exhaust port  1302  can be in fluid communication with a vacuum pump creating a vacuum in the cavity  1308 , and hence in the ventilation conduits  1304 ,  1306 , via the exhaust port  1302 . 
     The fluid blower may be operated in both directions. In other words, the fluid blower can be operated to draw fluid from the sample digestion station  206  towards the exhaust port  1302  to draw undesirable fumes from the vessels  302  via the first ventilation conduits  1304 , for instance. In some embodiments, the fluid blower can be operated to draw fluid from the sample cooling station  208  towards the exhaust port  1302  to draw undesirable fumes from the top of the vessels  302  during the cooling process, via the second ventilation conduits  1306 , for instance. In some embodiments, the fluid blower can be operated to blow fluid from the exhaust port  1302  towards the sample cooling station  208  to cool the vessels  302  via the second ventilation conduits  1306 , for instance. In these embodiments, a thermoelectric element can be provided to cool air within the second ventilation conduits  1306 , to increase the rate at which the vessels  302  are cooled by the ventilation unit  220 . A fluid valve can be provided to selectively open or close either one of the first and second ventilation conduits  1304 ,  1306 . One or more third ventilation conduits can also be provided. In such embodiments, the vessels  302  can be cooled by blowing cold fluid thereon via the first ventilation conduits  1304  while removing any undesirable fumes away from the vessels  302  using the third ventilation conduit(s). 
     The ventilation unit  220  can be operated in accordance with instructions stored on the memory of the controller  218 . For instance, the ventilation unit  220  can be operated to ventilate either one or both of the first and second ventilation conduits  1304 ,  1306 , if desired. 
     All of the pumps described herein may be equipped with multi-port valves so as to allow one pump to be permanently connected to several reservoirs, such as one or more reagents reservoirs  228 , one or more integrated reservoirs  606 , one or more washing reservoir  608 , one or more normalization fluid reservoirs  1014 , one or more cleaning agent reservoir, one or more external reservoir  699 , and the like. 
     The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present disclosure will be apparent to those skilled in the art, in light of a review of this disclosure. 
     The controller  118 ,  218  as described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof. Alternatively, the controller  118 ,  218  may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the controller  118 ,  218  may be stored on a storage media or a device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. Embodiments of the controller  118 ,  218  may also be considered to be implemented by way of a non-transitory computer-readable storage medium having a computer program stored thereon. The computer program may comprise computer-readable instructions which cause a computer, or more specifically the controller  118 ,  218  of the integrated system  100 ,  200 , to operate in a specific and predefined manner to perform the functions described herein. 
     Computer-executable instructions may be in many forms, including program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments. 
     Although the stations  204 ,  206 ,  208 ,  210 ,  212  described herein are shown to be spaced-apart from one another, the positions of the stations  204 ,  206 ,  208 ,  210 ,  212  can coincide with one another, i.e. be co-located. 
     Various aspects of the systems and methods described herein may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Although particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects. The scope of the following claims should not be limited by the embodiments set forth in the examples, but should be given the broadest reasonable interpretation consistent with the description as a whole.