Patent Publication Number: US-2022236153-A1

Title: Analyte concentrator system and methods of use

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional under 35 U.S.C. § 121 and claims the priority benefit of co-pending U.S. patent application Ser. No. 15/043,332, filed Feb. 12, 2016. The disclosure of the foregoing application is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to systems and methods for concentrating an analyte preparatory to analysis thereof. In particular, the present disclosure relates to methods for processing the effluent of an analyte concentrator to produce an eluent for eluting the analyte retained in the same or separate concentrator, and to systems implementing the same. The present disclosure further relates to an analyte concentrator system that connects the effluent outlet of an analyte concentrator to an eluent generation module, and to methods implementing the same. 
     2. Related Technology 
     In existing analyte concentrator systems (or columns), a fluid sample containing at least one analyte molecule of interest is introduced into an analyte concentrator column that retains at least some of the analyte molecules in the fluid sample. After washing any un-retained fluid sample or constituents thereof from the column, the retained analyte molecules are eluted from the column in a concentrated volume relative to the original fluid sample. For instance, an eluent having a chemical composition adapted for eluting the retained analyte molecules can be introduced into the column to elute the retained analyte. In this way, a fluid sample having a low concentration of analyte molecules can be concentrated for more robust analysis of the analyte. 
       FIG. 1  is a flowchart diagram illustrating a prior art analyte concentrator system  8  as known to those skilled in the art. As depicted in  FIG. 1 , an analyte sample  10  is introduced via input line  12  into an analyte concentrator  14 . Analyte concentrator  14  is configured to retain one or more analyte molecules of interest contained in analyte sample  10 . Accordingly, the analyte is retained in analyte concentrator  14 , while the fluid sample effluent is discharged via output line  16  to waste  18 . 
     A wash fluid  20  may also be optionally introduced via input line  22  into analyte concentrator  14 . Wash fluid  20  is configured to remove any un-retained sample (e.g., sample fluid or molecular component thereof) from analyte concentrator  14 . The wash effluent is also discharged via output line  16  to waste  18 . 
     After washing analyte concentrator  14 , an eluent  24  is introduced into analyte concentrator  14 . Eluent  24  is chemically configured to elute the analyte retained in analyte concentrator  14 . The eluted analyte molecules of interest are then discharged from analyte concentrator  14  (as a concentrated analyte sample) via output line  28  and introduced into analyte detector  30  for analysis. 
     One drawback to prior art system  8  and other existing concentrator systems is the presence of analyte molecules and/or contaminants in the wash fluid  20  and/or the eluent  24 . Indeed, the wash fluid  20  and/or eluent  24  may include the very analyte sought to be analyzed in analyte detector  30 . Even wash fluid and/or eluent generated from ultra-pure or nano-filtered water may not be entirely or even substantially free of the analyte molecules of interest. Thus, the amount or concentration of analyte eluted from analyte concentrator  14  may not represent the actual amount of analyte in analyte sample  10 . Instead, analyte concentrator  14  may have retained the analyte molecules contained in wash fluid  20 . In addition, the eluent itself may include analyte molecules; adding to the amount of analyte molecules present in the eluted analyte sample. Further, the eluent may include ionic contaminants from the water source that interfere with the analyte measurement. These additional sources of analyte molecules in the concentrated analyte sample can adulterate the sample and alter the analytical results. 
     Subtractive normalization or other techniques may be used to remove analytical (background) noise caused by analyte or ionic contaminants in the eluent and/or wash fluid. However, if the analyte sample only contained trace amounts (e.g., on the order of parts-per-billion (ppb) or even parts-per-trillion (ppt)) of the analyte molecules of interest, the background signal (or noise) from the additional analyte molecules in the eluent and/or wash fluid may overwhelm the analyte signal and negate accurate, quantitative measurement of the concentrated analyte molecules of interest. 
     Accordingly, it would be beneficial to provide systems and methods for concentrating an analyte using a eluent that is substantially free of the analyte molecule(s) of interest or ionic contaminants (e.g., to minimize and/or (substantially) eliminate background signal during analysis of the concentrated analyte). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, or to further clarify the above and other advantages and features of the present disclosure, a more particular description of the disclosure briefly described above will be rendered by reference to specific implementations and/or embodiments thereof which are illustrated in the appended drawings. While the drawings are generally drawn to scale for some example embodiments, it should be understood that the scale may be varied and the illustrated embodiments are not necessarily drawn to scale for all embodiments encompassed herein. 
       Furthermore, it will be readily appreciated that the components of the illustrative embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations, and that components within some figures are interchangeable with, or may supplement, features and components illustrated in other figures. Accordingly, understanding that the drawings depict only typical implementations and/or embodiments of the disclosure and are not, therefore, to be considered to be limiting of its scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a schematic flow diagram of an exemplary prior art system; 
         FIG. 2  illustrates a schematic flow diagram of an analyte concentrator system in accordance with an embodiment of the present disclosure; 
         FIG. 3  illustrates a schematic diagram of an analyte concentrator assembly useful in the analyte concentrator system of  FIG. 2  in accordance with an embodiment of the present disclosure; 
         FIGS. 4A and 4B  illustrate, respectively, schematic diagrams of an analyte concentrator assembly in a first ( 4 A) and second ( 4 B) configuration in accordance with an embodiment of the present disclosure; 
         FIGS. 5A and 5B  illustrate, respectively, schematic diagrams of an analyte concentrator system in a first ( 5 A) and second ( 5 B) configuration in accordance with another embodiment of the present disclosure; 
         FIGS. 6A and 6B  illustrate, respectively, schematic diagrams of an analyte concentrator assembly in a first ( 6 A) and second ( 6 B) configuration in accordance with another embodiment of the present disclosure; 
         FIG. 7  illustrates an exemplary eluent generation module in accordance with another embodiment of the present disclosure; and 
         FIG. 8  illustrates an exemplary analyte detection module in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Before describing the present disclosure in detail, it is to be understood that this disclosure is not limited to the specific parameters of the particularly exemplified systems, methods, apparatus, assemblies, products, processes, and/or kits, which may, of course, vary. It is also to be understood that much, if not all of the terminology used herein is only for the purpose of describing particular embodiments of the present disclosure, and is not necessarily intended to limit the scope of the disclosure in any particular manner. Thus, while the present disclosure will be described in detail with reference to specific configurations, embodiments, and/or implementations thereof, the descriptions are illustrative only and are not to be construed as limiting the scope of the claimed invention. 
     Various aspects of the present disclosure, including devices, systems, methods, etc., may be illustrated with reference to one or more exemplary embodiments or implementations. As used herein, the terms “exemplary embodiment” and/or “exemplary implementation” means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other embodiments or implementations disclosed herein. In addition, reference to an “implementation” of the present disclosure or invention includes a specific reference to one or more embodiments thereof, and vice versa, and is intended to provide illustrative examples without limiting the scope of the invention, which is indicated by the appended claims rather than by the following description. 
     Furthermore, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains. While a number of methods and materials similar or equivalent to those described herein can be used in the practice of the present disclosure, only certain exemplary materials and methods are described herein. 
     It will be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a “column” includes one, two, or more columns. Similarly, reference to a plurality of referents should be interpreted as comprising a single referent and/or a plurality of referents unless the content and/or context clearly dictate otherwise. Thus, reference to “columns” does not necessarily require a plurality of such columns. Instead, it will be appreciated that independent of conjugation; one or more columns are contemplated herein. 
     As used throughout this application the words “can” and “may” are used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Additionally, the terms “including,” “having,” “involving,” “containing,” “characterized by,” as well as variants thereof (e.g., “includes,” “has,” and “involves,” “contains,” etc.), and similar terms as used herein, including the claims, shall be inclusive and/or open-ended, shall have the same meaning as the word “comprising” and variants thereof (e.g., “comprise” and “comprises”), and do not exclude additional, un-recited elements or method steps, illustratively. 
     Various aspects of the present disclosure can be illustrated by describing components that are coupled, attached, connected, and/or joined together. As used herein, the terms “coupled”, “attached”, “connected,” and/or “joined” are used to indicate either a direct association between two components or, where appropriate, an indirect association with one another through intervening or intermediate components. In contrast, when a component is referred to as being “directly coupled”, “directly attached”, “directly connected,” and/or “directly joined” to another component, no intervening elements are present or contemplated. Thus, as used herein, the terms “connection,” “connected,” and the like do not necessarily imply direct contact between the two or more elements. In addition, components that are coupled, attached, connected, and/or joined together are not necessarily (reversibly or permanently) secured to one another. For instance, coupling, attaching, connecting, and/or joining can comprise placing, positioning, and/or disposing the components together or otherwise adjacent in some implementations. 
     As used herein, directional and/or arbitrary terms, such as “top,” “bottom,” “front,” “back,” “rear,” “left,” “right,” “up,” “down,” “upper,” “lower,” “inner,” “outer,” “internal,” “external,” “interior,” “exterior,” “proximal,” “distal,” and the like can be used solely to indicate relative directions and/or orientations and may not otherwise be intended to limit the scope of the disclosure, including the specification, invention, and/or claims. 
     To facilitate understanding, like reference numerals have been used, where possible, to designate like elements common to the figures. Furthermore, alternative configurations of a particular element may each include separate letters appended to the element number. Accordingly, an appended letter can be used to designate an alternative design, structure, function, implementation, and/or embodiment of an element or feature without an appended letter. Similarly, multiple instances of an element and or sub-elements of a parent element may each include separate letters appended to the element number. In each case, the element label may be used without an appended letter to generally refer to instances of the element or any one of the alternative elements. Element labels including an appended letter can be used to refer to a specific instance of the element or to distinguish or draw attention to multiple uses of the element. However, element labels including an appended letter are not meant to be limited to the specific and/or particular embodiment(s) in which they are illustrated. In other words, reference to a specific feature in relation to one embodiment should not be construed as being limited to applications only within said embodiment. 
     It will also be appreciated that where two or more values, or a range of values (e.g., less than, greater than, at least, and/or up to a certain value, and/or between two recited values) is disclosed or recited, any specific value or range of values falling within the disclosed values or range of values is likewise disclosed and contemplated herein. Thus, disclosure of an illustrative measurement or distance less than or equal to about 10 units or between 0 and 10 units includes, illustratively, a specific disclosure of: (i) a measurement of 9 units, 5 units, 1 units, or any other value between 0 and 10 units, including 0 units and/or 10 units; and/or (ii) a measurement between 9 units and 1 units, between 8 units and 2 units, between 6 units and 4 units, and/or any other range of values between 0 and 10 units. 
     Various modifications can be made to the illustrated embodiments without departing from the spirit and scope of the invention as defined by the claims. Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. It is also noted that systems, methods, apparatus, devices, products, processes, and/or kits, etc., according to certain embodiments of the present disclosure may include, incorporate, or otherwise comprise properties, features, components, members, and/or elements described in other embodiments disclosed and/or described herein. Thus, reference to a specific feature in relation to one embodiment should not be construed as being limited to applications only within said embodiment. 
     The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. 
     In the description, example systems, methods, and/or apparatus may be described with reference to one or more analytes or analyte molecules (of interest). It should be appreciated that as used herein, “analyte” can refer to a substance whose chemical constituent(s) are being analyzed (e.g., detected, isolated, separated, identified, measured, quantified, etc.) and/or the chemical constituent(s) themselves (i.e., a chemical substance that is the subject of chemical analysis, a substance or chemical constituent that is of interest in an analytical procedure, etc.). Thus, an illustrative fluid (e.g., drinking water) sample can be and/or constitute an analyte having or comprising one or more analyte molecules of interest disposed or contained therein. Alternatively or in addition, the one or more analyte molecules of interest disposed or contained in the drinking water sample can likewise constitute analyte(s). Thus, where appropriate, an analyte (i.e., fluid sample) can be introduced into a concentrator column configured to retain the analyte (i.e., molecule(s) of interest) without departing from the scope of this disclosure. 
     Moreover, as used herein, a “molecule” or “molecule of interest” includes other matter of interest, including but not limited to cells, particles, compounds, crystals, aggregates, etc. For instance, in at least one embodiment, a molecule of interest can comprise phosphate, sulfate, nitrate, nitride, bromate, chlorite, chloroform, bromoform, asbestos, or another molecular compound, including acids, hydrocarbons, and the like. In other embodiments, a molecule of interest can comprise a (charged) elemental molecule, such as fluoride, chloride, bromide, arsenic, barium, chromium, etc., as well as compounds including the same. Thus, reference to a “molecule” or “molecule of interest” should not b e construed as being limited to a (single) molecule, per se. Rather, such terms should be construed broadly to include any substance or matter (e.g., that may be present or included in a liquid sample). 
     In addition, example systems, methods, and/or apparatus may be described with reference to one or more ions, ionic molecules, ionized molecules, charged molecules, and the like. It will be appreciated that such terms are illustrative and/or representative of analytes, in general, and should be understood accordingly. 
     It is further to be understood that some of the drawings included herewith, and which are referenced herein, are diagrammatic and schematic representations of example embodiments, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for some embodiments, the drawings are not necessarily drawn to scale for all contemplated embodiments. No inference should therefore be drawn from the drawings as to the necessity of any scale. 
     Furthermore, as indicated above, in the exemplary embodiments illustrated in the figures, like structures will be provided with similar reference designations, where possible. Specific language will be used herein to describe the exemplary embodiments. Nevertheless it will be understood that no limitation of the scope of the disclosure is thereby intended. It is to be understood that the drawings are diagrammatic and schematic representations of various embodiments of this disclosure, and are not to be construed as limiting the scope of the disclosure, unless such shape, form, scale, function, or other feature is expressly described herein as essential. 
     Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of this disclosure. Unless a feature is described as requiring another feature in combination therewith, any feature herein may be combined with another feature of a same or different embodiment disclosed herein. Furthermore, various well-known aspects of illustrative systems, methods, apparatus, and the like are not described herein in particular detail in order to avoid obscuring aspects of the example embodiments. 
     Exemplary embodiments of the present disclosure generally relate to systems and methods for concentrating an analyte preparatory for analysis thereof. In particular, the present disclosure relates to methods for processing the effluent of an analyte concentrator to produce an eluent for eluting an analyte retained in the same or separate concentrator, and to systems implementing the same. The present disclosure further relates to an analyte concentrator system that connects the effluent outlet of an analyte concentrator to an eluent generation module, and to methods implementing the same. 
     Reference will now be made to the figures to describe various aspects of example embodiments of the disclosure.  FIG. 2  depicts a flow diagram of an analyte concentrator system  50  incorporating some features of the present disclosure. In a first embodiment, analyte concentrator system  50  comprises an analyte concentrator assembly  56  fluid-coupled to an eluent generation module  64  via an (effluent) output line  62 . As depicted in  FIG. 2 , an analyte sample  52  is introduced via (analyte) input line  54  into an analyte concentrator assembly  56 . Analyte concentrator assembly  56  is configured to retain one or more analyte molecules of interest contained in analyte sample  52 . Accordingly, at least a portion of the analyte molecule(s) is retained in analyte concentrator assembly  56 , while the fluid sample effluent (e.g., a substantially analyte-free sample effluent) is discharged from analyte concentrator assembly  56  via output line  62 . 
     Substantially analyte-free fluid sample effluent discharged from analyte concentrator assembly  56  is routed (e.g., fluidly) via output line  62  from analyte concentrator assembly  56  to eluent generation module  64  (e.g., where the substantially analyte-free effluent can be used to generate a substantially analyte-free eluent). Thus, unlike existing systems in which an effluent is discharged into waste (see  FIG. 1 ), embodiments of the present disclosure can use the substantially analyte-free effluent to generate a substantially analyte-free eluent. Accordingly, whereas existing systems rely on a separate fluid source to generate eluent; adding to labor costs, decreasing efficiencies, and resulting in eluent that may contain a substantial amount of the analyte molecule of interest, embodiments of the present disclosure route the effluent discharged from an analyte concentrator assembly specifically designed to retain the analyte molecule of interest (thereby discharging a substantially analyte-free effluent) into an eluent generation module to produce a eluent therefrom that is, likewise, substantially free of the analyte molecule of interest retained in the analyte concentrator assembly. 
     As used herein, “substantially analyte-free,” “substantially free of the analyte (molecule(s)),” and the like can be used to refer to a fluid, sample, and/or product having, including, comprising and/or containing less than or equal to a threshold amount of a particular analyte (of interest). For instance, the threshold amount can be measured in terms of molar concentration, mass, etc. In one embodiment, “substantially analyte-free,” “substantially free of the analyte (molecule(s)),” and the like can refer to less than or equal to nano-molar, pico-molar, femto-molar, atto-molar, etc. Alternatively, “substantially analyte-free,” “substantially free of the analyte (molecule(s)),” and the like can refer to less than or equal to a value (whole number or decimal value) of nano-grams, pico-grams, femto-grams, atto-grams, etc. per unit of volume (e.g., liter, kiloliter, etc.). 
     The threshold amount can also be measured in terms of quantity-per-quantity (e.g., parts (analyte) per notation (reference)). Accordingly, this (set of) pseudo unit(s) can be used to describe the small values of the analyte concentration (i.e., substantially free) in dimensionless quantities or terms (e.g., mole fraction, mass fraction, etc.). Specifically, the threshold can be measured in terms of ppm (parts-per-million, 10 −6 ), ppb (parts-per-billion, 10 −9 ), ppt (parts-per-trillion, 10 −12 ) and ppq (parts-per-quadrillion), etc.; where parts can comprise any value (whole number or decimal value). Accordingly, “substantially analyte-free,” “substantially free of the analyte (molecule(s)),” and the like can refer to less than or equal to one part analyte per billion parts reference. The unit “1 ppb” can be used for a mass fraction if the analyte is present at one-millionth of a gram per gram of sample solution, etc. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL. Therefore, it is common to equate 1 gram of water with 1 mL of water. Consequently, ppb corresponds to 1 μg/L water (or water based fluid, in some instances). 
     In a further embodiment, eluent generated in eluent generation module  64  (of or from the analyte sample effluent) can similarly be routed (e.g., fluidly) via an (eluent) input line  70  from eluent generation module  64  to analyte concentrator assembly  56 , where the eluent can be used to elute an analyte retained in analyte concentrator assembly  56 . 
     In at least one further embodiment, the eluted analyte can be routed (e.g., fluidly) via an (analyte) output line  76  from analyte concentrator assembly  56  to an analyte detection module  78 , where the analyte can be analyzed (e.g., the presence of the analyte can be detected, the identity of the analyte can be determined, the quantity and/or quality of the analyte can be measured, etc.). After passing through analyte detection module  78 , fluid sample can be discharged via output line  82  to waste  68 . 
     An optional wash fluid can also be introduced into analyte concentrator assembly  56  via a separate wash fluid input line (not shown). Alternatively, the wash fluid can be introduced via input line  54 . The wash fluid can comprise a pre-wash (e.g., configured to remove any foreign and/or undesirable matter from analyte concentrator assembly  56  and/or to prepare analyte concentrator assembly  56  to receive analyte sample  52 ). Alternatively, or in addition, the wash fluid can comprise a post-wash (e.g., configured to remove any un-retained sample (e.g., analyte sample fluid or molecular component thereof)) from analyte concentrator assembly  56 . A wash fluid effluent can also be discharged from analyte concentrator assembly  56  via output line  62 . Alternatively, the wash fluid effluent can be discharged via a separate output line (not shown). Those skilled in the art will appreciate, however, that certain embodiment may not include a wash fluid and/or a washing step as described above. Instead, in some embodiments, the volume of analyte sample  52 , for instance, may be sufficient to ensure that a suitable amount of analyte sample  52  passes through analyte concentrator assembly  56 , a suitable amount of analyte is retained by analyte concentrator assembly  56 , and/or a suitable amount of effluent passes out of analyte concentrator assembly  56 , etc. 
     Output line  62  can optionally include an (effluent) output valve  66  configured to selectively open one of optional lines  62   a,    62   b,  and  62   c  (and selectively closing the other lines). For instance, output valve  66  can selectively open line  62   a,  connecting effluent output line  62  to eluent generation module  64 , while selectively closing lines  62   b  and  62   c.  Alternatively, output valve  66  can selectively open line  62   b,  connecting output line  62  to a waste (drain)  68 , while selectively closing lines  62   a  and  62   c.  Furthermore, output valve  66  can selectively open line  62   c,  connecting output line  62  to an effluent (purified water/mobile phase) storage member  63 , while selectively closing lines  62   a  and  62   b.  In an illustrative operation, the (substantially analyte-free) sample effluent passing out of analyte concentrator assembly  56  via effluent output line  62  can be selectively routed via line  62  a to eluent generation module  64  or via line  62   c  to storage member  63 . Effluent stored in storage member  63  can be routed via line  62   d  to eluent generation module  64 . In some embodiments, effluent stored in storage member  63  can be useful in a variety of other applications, such as making (generating) standards free from analyte ions using the stored effluent as a diluent (which can be either done offline volumetrically or inline via a flowing stream). Similarly, the optional wash fluid effluent (e.g., substantially analyte-free wash fluid effluent) passing out of analyte concentrator assembly  56  (e.g., via effluent output line  62 ) can be selectively routed via line  62   a  to eluent generation module  64  or via line  62   c  to storage member  63  (e.g., to generate additional substantially analyte-free eluent and/or to wash the eluent generation module  64 ). Alternatively, the wash fluid effluent passing out of analyte concentrator assembly  56  via effluent output line  62  can be selectively routed via line  62   b  to waste  68 . 
     Eluent line  70  can also optionally include a valve  72  (e.g., eluent valve) configured to selectively open one of optional lines  70   a  and  70   b  (and selectively closing the other line). For instance, valve  72  can selectively open line  70   a,  connecting input line  70  to analyte concentrator assembly  56 , while selectively closing line  70   b.  Alternatively, output valve  72  can selectively open line  70   b,  connecting eluent line  70  to an optional storage member  74 , while selectively closing line  70   a.  In an illustrative operation, the substantially analyte-free eluent can pass out of eluent generation module  64  via eluent line  70  and can be selectively routed via line  70   b  to optional storage  74 . 
     Storage  74  can comprise a receptacle in some embodiments. Accordingly, the substantially analyte-free eluent can be stored in the receptacle for later use. For instance, a line  70   c  connects storage  74  to analyte concentrator assembly  56 . Accordingly, substantially analyte-free eluent can pass out of storage  74  and into analyte concentrator assembly  56  to elute the retained analyte. Storage  74  can overcome a potential problem in the configuration of system  50 . Specifically, analyte concentrator assembly  56  may not be prepared (e.g., sufficiently washed, etc.) to receive the eluent at the time it is discharged from eluent generation module  64  in some embodiments and/or applications (e.g., during a certain run or assay). Thus, storage  74  can provide a delay sufficient to provide time necessary to (fully) prepare analyte concentrator assembly  56  prior to introducing the eluent therein. 
     Alternatively, eluent line  70  can be configured to provide a sufficient delay in delivering the eluent to analyte concentrator assembly  56 . For instance, eluent line  70  can include a sample loop, as known in the art. The sample loop can be connected (e.g., fluidly) to analyte concentrator assembly  56 , can be used to precisely load a known volume of the sample into the concentrator column, and/or can provide the delay described above. Such a delay may be necessary in order to complete the processing of analyte sample  52  (through analyte concentrator assembly  56 ) and/or may potentially eliminate the need for a separate storage  74  and/or valve  72 . Alternatively, the substantially analyte-free eluent can pass out of eluent generation module  64  via eluent line  70  and can be selectively routed via line  70   a  into analyte concentrator assembly  56  to elute the retained analyte. 
     Output line  76  can also optionally include a valve  80  (e.g., eluted analyte valve) configured to selectively open one of optional lines  76   a  and  76   b  (and selectively closing the other line). For instance, valve  80  can selectively open line  76   a,  connecting output line  76  to analyte detection module  78 , while selectively closing line  76   b.  Alternatively, output valve  80  can selectively open line  76   b,  connecting output line  76  to waste  68 , while selectively closing line  76   a.  In an illustrative operation, the eluted analyte can pass out of analyte concentrator assembly  56  via output line  76  and can be selectively routed via line  76   a  to analyte detection module  78 . On the other hand, a wash fluid flowing through system  50  can pass out of analyte concentrator assembly  56  via output line  76  and can be selectively routed via line  76   b  to waste  68 . 
     Output line  82  can also optionally include an output valve  84  configured to selectively open one of optional lines  82   a  and  82   b  (and selectively closing the other line). For instance, valve  84  can selectively open line  82   a,  connecting output line  82  to waste  68 , while selectively closing line  82   b.  Alternatively, output valve  84  can selectively open line  82   b,  connecting output line  82  to analyte detection module  78 , while selectively closing line  82   a.  In an illustrative operation, fluid sample can be recirculated back into at least a portion of analyte detection module  78  through a line  82   b  (to regenerate one or more components thereof). 
     Recirculated sample can be discharged from analyte detection module  78  via an output line  86 . Output line  86  can also optionally include an output valve  88  configured to selectively open one of optional lines  86   a  and  86   b  (and selectively closing the other line). For instance, valve  88  can selectively open line  86   a,  connecting output line  86  to waste  68 , while selectively closing line  86   b.  Alternatively, output valve  88  can selectively open line  86   b,  connecting output line  86  to elution generation module  64 , while selectively closing line  86   a.  In an illustrative operation, fluid sample can be recirculated back into at least a portion of elution generation module  64  (to regenerate one or more components thereof). 
     Those skilled in the art will appreciate that different embodiments of system  50  can comprise different combinations of the components described above and/or illustrated in  FIG. 2 . Accordingly, system  50  according to one or more specific embodiments need not include each and every component described above and/or illustrated in  FIG. 2 . Similarly, a variety of methods described herein can involve passing one or more fluid samples through system  50  or one or more components thereof. Accordingly, such methods (or other methods) need not include each and every step described above and/or illustrated in  FIG. 2 . 
     Furthermore, various components of system  50  and/or methods involving the same (or other methods) will be discussed in further detail below. It will likewise be appreciated that such components and/or method steps are illustrative only and that various embodiments can include more than or fewer than the described and/or illustrated components and/or method steps. 
       FIG. 3  depicts a more specific illustrative analyte concentrator assembly  56   a  useful in an illustrative system  50  (e.g., which can be used as analyte concentrator assembly  56 —see e.g.,  FIG. 2 ). As depicted in  FIG. 3 , analyte concentrator assembly  56   a  comprises an analyte concentrator  90  having an inlet opening  92  and an outlet opening  94 . Alternatively, analyte concentrator  90  can have a plurality of inlet openings  92  and/or a plurality of outlet openings  94 . Analyte concentrator assembly  56   a  further comprises an optional inlet valve  96 , selectively coupling inlet opening  92  of analyte concentrator  90  to (analyte sample) input line  54  and/or (eluted analyte sample) output line  76  (as similarly illustrated in  FIG. 2 ). In addition, analyte concentrator assembly  56   a  comprises an optional outlet valve  98 , selectively coupling outlet opening  94  of analyte concentrator  90  to (effluent) output line  62  and/or (eluent) input line  70  (as similarly illustrated in  FIG. 2 ). Accordingly, analyte concentrator  90  may only require a single inlet opening  92  and/or a single outlet opening  94  in certain embodiments. 
     In some embodiments, analyte concentrator  90  can comprise a concentrator column (e.g., as known in the art). Such concentrator columns can have and/or comprise an encircling side wall  90   a  extending from a first end  90   b  of the concentrator column  90  to an opposing second end  90   c  of the concentrator column  90  and at least partially bounding an internal cavity  90   d.  Such concentrator columns  90  can also have and/or comprise inlet opening  92  disposed at the first end  90   b  and in fluid communication with the internal cavity  90   d  and outlet opening  94  disposed at the second end  90   c  and in fluid communication with the internal cavity  90   d.    
     Regardless of specific components and/or configurations, analyte concentrator assembly  56   a  can have and/or include at least one analyte retention mechanism  91 . For instance, analyte concentrator column  90  can, illustratively, be and/or comprise an ion exchange-type concentrator column. Such ion-exchange concentrator columns  90  can have and/or include an analyte retention mechanism  91  disposed within internal cavity  90   d.  In at least one embodiment, analyte retention mechanism  91  can comprise ion-exchange chromatography material (e.g., resin, polymeric substrate, agarose, beads, and/or other suitable chromatography material). A typical ion-exchange concentrator column  90  is packed with the chromatography material such that the material is disposed and/or retained therein (e.g., in the internal cavity  90   d  thereof). Such material can be configured to carry a net charge (e.g., in one or more (specific) pH solutions). Electrostatic interactions between the net charged chromatography material and charged analyte molecules can cause the chromatography material to retain (e.g., bind to) the analyte molecules. Salt and/or acid concentration in solution can be used to manipulate the chromatography material into binding or releasing certain types of molecules of interest. 
     Thus, ion exchange-type concentrator columns  90  can be configured to retain one or more molecular component(s) based on one or more ionic and/or charge-related characteristics thereof (e.g., ionic state in a particular pH of solution). Specifically, some (anionic) concentrator columns  90  can be configured to retain certain negatively-charged (anionic) molecules with positively-charged chromatography material. Accordingly, one or more anionic analytes disposed in a fluid sample may be retained in the column, while the fluid sample effluent is discharged from the column. Alternatively, some (cationic) concentrator columns can be configured to retain certain positively-charged (cationic) molecules with negatively-charged chromatography material. Accordingly, one or more cationic analytes disposed in a fluid sample may be retained in the column  90 , while the fluid sample effluent is discharged from the column. Other types of concentrator columns  90  are also known in the art and contemplated herein. 
     Indeed, a wide variety of analyte concentrator assemblies  56   a  and/or analyte concentrators  90  can be configured to retain one or more molecular component(s) based on specific chemical and/or structural properties. Each can include an analyte retention mechanism(s)  91  specifically configured to retain one or more analyte molecules of interest while allowing the sample effluent to be discharged. Accordingly, a variety of analyte retention mechanisms  91  are known in the art and contemplated herein. 
     Those skilled in the art will appreciate that analyte concentrator  90 , as depicted in  FIG. 3 , can also be preferably configured for counter-current elution. Specifically, (eluent) input line  70  is (selectively, fluidly) connected to analyte concentrator  90  via outlet opening  94  (similar and/or adjacent to (effluent) output line  62 ), and (eluted analyte sample) output line  76  is (selectively, fluidly) connected to analyte concentrator  90  via inlet opening  92 . Accordingly, as discussed in further detail below, an analyte sample  52  (see e.g.,  FIG. 2 ) may be introduced into and flow through analyte concentrator  90  in a first fluid direction  93  a (e.g., from inlet opening  92  toward outlet opening  94 ), while an eluted concentrated analyte sample may be eluted and discharged from analyte concentrator  90  in a second fluid direction  93   b  (e.g., from outlet opening  94  toward inlet opening  92 ). Alternative embodiments can b e configured for uniform current flow operation without departing from the scope of this disclosure. 
     In at least one embodiment, the volume of eluent introduced into analyte concentrator  90  (via port  94  and/or to elute an analyte retained therein) can be substantially less that the volume of the original analyte sample  52  introduced into analyte concentrator assembly  56   a  and/or analyte concentrator  90  thereof (via inlet  92 ) during a specific run or assay. Accordingly, the eluted analyte sample can be significantly concentrated relative to the original analyte sample. For instance, the eluted analyte sample can be at least, up to, greater than, about, or between 2-fold, 5-fold, 10-fold, 20-fold, 50-fold, 100-fold, 200-fold, 500-fold, 1000-fold, 10,000-fold, 100,000-fold, or more concentrated relative to the original analyte sample. In some embodiments, for example, analyte concentrator  90  (or the analyte retention mechanism  91  thereof) can initially retain analyte molecules adjacent to inlet opening  92 . Accordingly, the retained analytes can elute from analyte concentrator  90  in an eluent volume significantly less than the total volume of the original analyte sample. Thus, the eluted analyte sample can be or comprise a concentrated, eluted analyte sample in some embodiments. 
     In one or more embodiments, an analyte concentrator assembly can also include one or more multi-port (master) fluid valves. Such a fluid valve can coordinate fluid flow through the system  50  (see e.g.,  FIG. 2 ) and/or a concentrator column thereof. In some embodiments, for instance, a multi-port (master) fluid valve can coordinate fluid flow in and out of an concentrator column (such as concentrator column  90  illustrated in  FIG. 3 ) and/or illuminate the need for more or more of optional valves  66 ,  72 ,  80 ,  84 , and  88 . 
       FIGS. 4A and 4B  illustrate, schematically, an analyte concentrator assembly  56   b  comprising a concentrator column  90  and an illustrative multi-port (master) fluid valve  100  in a first valve configuration ( FIG. 4A ) and a second valve configuration ( FIG. 4B ). Fluid valve  100  can also be useful in other embodiments of the present disclosure. As illustrated in  FIGS. 4A and 4B , fluid valve  100  comprises six selectively connectable ports  102  and is selectively configurable between the first and second valve configurations (to selectively connect different combinations of the plurality of ports). Fluid valves having less than six or greater than six ports are also contemplated herein. 
     In both the first and second valve configurations (illustrated in  FIGS. 4A and 4B , respectively), inlet opening  92  of analyte concentrator  90  is fluid coupled with a concentrator inlet port  102   a.  Similarly, outlet opening  94  of analyte concentrator  90  is fluid coupled with a concentrator outlet port  102   d.  As discussed in further detail below, selective fluid communication between concentrator inlet port  102   a  and adjacent ports  102   b  and  102   f  alternates between the first and second valve configurations, respectively. Accordingly, inlet opening  92  is selectively fluid connectable with port  102   b  and with port  102   f.  Likewise, selective fluid communication between concentrator outlet port  102   d  and adjacent ports  102   c  and  102   e  alternates between the first and second valve configurations, respectively. Accordingly, outlet opening  94  is selectively fluid connectable with port  102   c  and with port  102   e.    
     As depicted in  FIG. 4A , in the first valve configuration, analyte input line  54  is connected to a first fluid inlet port  102   b,  which is in fluid communication with concentrator inlet port  102   a  through the first fluid path of fluid valve  100  (in the first valve configuration). Accordingly, because inlet opening  92  of analyte concentrator  90  is in fluid communication with concentrator inlet port  102   a,  analyte input line  54  is in fluid communication with analyte concentrator  90  in the first valve configuration. 
     Likewise, in the first valve configuration, effluent output line  62  is connected to a first fluid outlet port  102   c,  which is in fluid communication with concentrator outlet port  102   d  through the first fluid path of fluid valve  100  (in the first valve configuration). Accordingly, because outlet opening  94  of analyte concentrator  90  is in fluid communication with concentrator outlet port  102   d,  effluent output line  62  is in fluid communication with analyte concentrator  90  in the first valve configuration. 
     In operation, in the first valve configuration, an analyte sample  52  (see e.g.,  FIG. 2 ) passing through analyte input line  54  is introduced into fluid valve  100  at first fluid inlet port  102   b  and passes (fluidly) within the first internal fluid valve flow path of fluid valve  100  to concentrator inlet port  102   a,  and then exits fluid valve  100  through concentrator inlet port  102   a  to pass (fluidly), via an optional valve line  100   a,  into analyte concentrator  90  via inlet opening  92 . As described above, analyte molecules disposed in the analyte sample ( 52 ) are retained in analyte concentrator  90  by means of one or more analyte retention mechanisms ( 91 ). The substantially analyte-free sample effluent (i.e., un-retained fluid sample and/or flow-through) passes (fluidly) out of analyte concentrator  90  via outlet opening  94 . The effluent is then introduced into fluid valve  100  at concentrator outlet port  102   d  via an optional valve line  100   b.  The effluent then passes (fluidly) within the first internal fluid valve flow path of fluid valve  100  to first fluid outlet port  102   c,  and then exits fluid valve  100  through fluid outlet port  102   c  to pass (fluidly) through effluent output line  62  (e.g., to eluent generation module  64  as depicted in  FIG. 2 ). 
     In the first valve configuration, the first internal fluid flow path also includes a fluid connection between second fluid inlet port  102   e  and second fluid outlet port  102   f.  Accordingly, a fluid passing through eluent line  70  is introduced into fluid valve  100  at second fluid inlet port  102   e.  The fluid then passes (fluidly) within the first internal fluid flow path of fluid valve  100  to second fluid outlet port  102   f,  and then exits fluid valve  100  through second fluid outlet port  102   f  to pass (fluidly) through output line  76  (e.g., to waste  68  or analyte detection module  78  as depicted in  FIG. 2 ). Accordingly, fluid delivered to fluid valve  100  via port  102   e  (in the first valve configuration) bypasses analyte concentrator  90  and passes directly to output line  76 . 
     However, as illustrated in  FIG. 4B , in the second valve configuration, (substantially analyte-free eluent) fluid passing through eluent line  70  (or a sub-line thereof), is introduced into fluid valve  100  via second fluid inlet port  102   e,  which is in fluid communication with opening  94  of analyte concentrator  90  via port  102   d  and valve line  100   b.  Accordingly, the substantially analyte-free eluent exits fluid valve  100  via port  102   d  and is introduced into analyte concentrator  90  via valve line  100   b  (in a direction opposite the flow of the analyte sample  52  into analyte concentrator  90  (i.e., in a counter-current direction)). As indicated above, the substantially analyte-free eluent can be chemically configured to elute the analyte molecules retained in analyte concentrator  90  (or by the analyte retention mechanism  91  thereof). 
     The (concentrated) eluted analyte sample exits analyte concentrator  90  via opening  92  and is introduced into fluid valve  100  at port  102   a  by means of valve line  100   a.  The concentrated, eluted analyte sample then passes to second fluid outlet port  102   f  via the second internal fluid flow path of fluid valve  100  (in the second valve configuration), and then exits fluid valve  100  through second fluid outlet port  102   f  to pass (fluidly) through output line  76  (e.g., to analyte detection module  78  as depicted in  FIG. 2 ). 
     Furthermore, in the second valve configuration, fluid passing through line  54  enters fluid valve  100  via first fluid inlet port  102   b  and passes directly out of fluid valve  100  via the second internal fluid valve flow path and first fluid outlet port  102   c,  and line  62  fluid-coupled therewith. 
       FIGS. 5A and 5B  depict, respectively, flow diagrams of an analyte concentrator system  50   a  in a first system configuration ( FIG. 5A ) and a second system configuration ( FIG. 5B ). Like elements between analyte concentrator system  50   a  and analyte concentrator system  50  are identified with like reference numerals. Analyte concentrator system  50   a  can be configured substantially similar to analyte concentrator system  50  (see e.g.,  FIG. 2 ), with one or more of the following (or other) described and/or depicted differences. In particular, analyte concentrator system  50   a  can include an analyte concentrator assembly  56   c  comprising a first concentrator column  90   a  and a second concentrator column  90   b.    
     As depicted in  FIG. 5A , in a first system configuration, analyte sample  52  is introduced via (analyte) input line  54  into concentrator column  90   a  of analyte concentrator assembly  56   c.  At least a portion of one or more analyte molecule(s) of interest contained and/or disposed in analyte sample  52  is retained in concentrator column  90   a,  while an analyte sample effluent is discharged therefrom. The fluid sample effluent discharged from concentrator column  90   a  is routed (e.g., fluidly) via output line  62  from analyte concentrator assembly  56   c  and/or concentrator column  90   a  thereof, to eluent generation module  64  (e.g., where the substantially analyte-free effluent can be used to generate a substantially analyte-free eluent). Eluent generated in eluent generation module  64  (of or from the analyte sample effluent) can similarly be routed (e.g., fluidly) via an (eluent) input line  70  from eluent generation module  64  to analyte concentrator assembly  56   c  and/or concentrator column  90   b  thereof, where the eluent can be used to elute an analyte retained in concentrator column  90   b  (as described in further detail below in relation to  FIG. 5B ). 
     The analyte eluted from concentrator column  90   b  is routed (e.g., fluidly) via (analyte) output line  76  from analyte concentrator assembly  56   c  and/or concentrator column  90   b  thereof, to an analyte detection module  78 , where the analyte can be analyzed. After passing through analyte detection module  78 , fluid sample can be discharged via output line  82 . 
     As indicated above, a wash fluid can also be (optionally) introduced into analyte concentrator assembly  56   c  and/or concentrator column  90   a  thereof via a separate wash fluid input line (not shown). Alternatively, the wash fluid can be introduced via input line  54 . The wash fluid effluent can also be discharged from analyte concentrator assembly  56   c  and/or concentrator column  90   a  thereof via output line  62 . Alternatively, the wash fluid effluent can be discharged via a separate wash fluid output line (not shown). 
     One or more of the valves described previously can also be incorporated into system  50   a,  as depicted in  FIGS. 5A and 5B , to alter the flow of fluid sample through system  50   a.  Recirculation of analyzed fluid sample can similarly occur as previously described. In at least one embodiment, a waste line  89  can carry recirculated or other fluid from eluent generation module  64  to waste  68 . In addition, no fluid sample storage element (such as storage  74  depicted in  FIG. 2 ) is required to operate system  50   a  effectively in one or more embodiments. Specifically, no delay is necessarily required because the eluent generated from the effluent of concentrator column  90   a  is introduced into concentrator column  90   b  to eluent an analyte already disposed and/or retained therein. Said analyte is retained in concentrator column  90   b  as follows. 
     As depicted in  FIG. 5B , in a second system configuration, analyte sample  52  is introduced via (analyte) input line  54  into concentrator column  90   b  of analyte concentrator assembly  56   c.  At least a portion of one or more analyte molecule(s) of interest contained and/or disposed in analyte sample  52  is retained in concentrator column  90   b,  while an analyte sample effluent is discharged therefrom. The fluid sample effluent discharged from concentrator column  90   b  is routed (e.g., fluidly) via output line  62  from analyte concentrator assembly  56   c  and/or concentrator column  90   b  thereof, to eluent generation module  64  (e.g., where the substantially analyte-free effluent can be used to generate a substantially analyte-free eluent). Eluent generated in eluent generation module  64  (of or from the analyte sample effluent) can similarly be routed (e.g., fluidly) via an (eluent) input line  70  from eluent generation module  64  to analyte concentrator assembly  56   c  and/or concentrator column  90   a  thereof, where the eluent can be used to elute an analyte retained in concentrator column  90   a  (as described above in relation to  FIG. 5A ). 
     The analyte eluted from concentrator column  90   a  is routed (e.g., fluidly) via (analyte) output line  76  from analyte concentrator assembly  56   c  and/or concentrator column  90   a  thereof, to analyte detection module  78 , where the analyte can be analyzed. After passing through analyte detection module  78 , fluid sample can be discharged via output line  82 . 
     As indicated above, no delay is necessarily required in operating system  50   a  because the eluent generated from the effluent of concentrator column  90   b  is introduced into concentrator column  90   a  to eluent an analyte already disposed and/or retained therein. 
     Those skilled in the art will again appreciate that different embodiments of system  50   a  can comprise different combinations of the components described above and/or illustrated in  FIGS. 5A and 5B . Accordingly, system  50   a  according to one or more specific embodiments need not include each and every component described above and/or illustrated in  FIGS. 5A and 5B . Similarly, the method described above in relation to system  50   a  can involve passing one or more fluid samples through one or more components thereof. Accordingly, such method (or other method) need not include each and every step described above and/or illustrated in  FIGS. 5A and 5B . 
     As indicated above, an analyte concentrator assembly can also include one or more multi-port (master) fluid valves.  FIGS. 6A and 6B  illustrate, schematically, an analyte concentrator assembly  56   d  comprising a first concentrator column  90   a,  a second concentrator column  90   b,  and an illustrative multi-port (master) fluid valve  101  in a first valve configuration ( FIG. 6A ) and a second valve configuration ( FIG. 6B ). Fluid valve  100  can also be useful in other embodiments of the present disclosure. As illustrated in  FIGS. 6A and 6B , fluid valve  101  comprises ten selectively connectable ports  103  and is selectively configurable between the first and second valve configurations (to selectively connect different combinations of the plurality of ports). Fluid valves having less than ten or greater than ten ports are also contemplated herein. 
     In both the first and second valve configurations (illustrated in  FIGS. 6A and 6B , respectively), inlet opening  92   a  of first analyte concentrator  90   a  is fluid coupled with a first concentrator inlet port  103   b.  Similarly, outlet opening  94   a  of first analyte concentrator  90   a  is fluid coupled with a first concentrator outlet port  103   e.  Likewise, inlet opening  92   b  of second analyte concentrator  90   b  is fluid coupled with a second concentrator inlet port  103   j  and outlet opening  94   b  of second analyte concentrator  90   b  is fluid coupled with a second concentrator outlet port  103   g.    
     As discussed in further detail below, selective fluid communication between first concentrator inlet port  103   b  and adjacent ports  103   a  and  103   c  alternates between the first and second valve configurations, respectively. Accordingly, inlet opening  92   a  of first analyte concentrator  90   a  is selectively fluid connectable with port  103   a  and with port  103   c.  Likewise, selective fluid communication between first concentrator outlet port  103   e  and adjacent ports  103   f  and  103   d  alternates between the first and second valve configurations, respectively. Accordingly, outlet opening  94   a  is selectively fluid connectable with port  103   f  and with port  103   d.    
     Furthermore, selective fluid communication between second concentrator inlet port  103   j  and adjacent ports  103   i  and  103   a  alternates between the first and second valve configurations, respectively. Accordingly, inlet opening  92   b  of second analyte concentrator  90   b  is selectively fluid connectable with port  103   i  and with port  103   a.  Likewise, selective fluid communication between second concentrator outlet port  103   g  and adjacent ports  103   h  and  103   f  alternates between the first and second valve configurations, respectively. Accordingly, outlet opening  94   b  is selectively fluid connectable with port  103   h  and with port  103   f.    
     As depicted in  FIG. 6A , in the first valve configuration, analyte input line  54  is connected to a first fluid inlet port  103   a,  which is in fluid communication with first concentrator inlet port  103   b  through the first internal fluid path of fluid valve  101  (in the first valve configuration). Accordingly, because inlet opening  92   a  of first analyte concentrator  90   a  is in fluid communication with concentrator inlet port  103   b,  analyte input line  54  is in fluid communication with first analyte concentrator  90   a  in the first valve configuration. 
     Likewise, in the first valve configuration, effluent output line  62  is connected to first fluid outlet port  103   f,  which is in fluid communication with first concentrator outlet port  103   e  through the first internal fluid path of fluid valve  101  (in the first valve configuration). Accordingly, because outlet opening  94   a  of first analyte concentrator  90   a  is in fluid communication with concentrator outlet port  103   e,  effluent output line  62  is in fluid communication with first analyte concentrator  90   a  in the first valve configuration. 
     Furthermore, in the first valve configuration, (eluent) input line  70  is connected to a second fluid inlet port  103   h,  which is in fluid communication with second concentrator outlet port  103   g  through the first internal fluid path of fluid valve  101  (in the first valve configuration). Accordingly, because outlet opening  94   b  of second analyte concentrator  90   b  is in fluid communication with second concentrator outlet port  103   g,  (eluent) input line  70  is in fluid communication with second analyte concentrator  90   b  in the first valve configuration. 
     Likewise, in the first valve configuration, (eluted analyte sample) output line  76  is connected to second fluid outlet port  103   c,  which is in fluid communication with connector ports  103   d,    103   i  through the first internal fluid path of fluid valve  101  (in the first valve configuration). Connector ports  103   d,    103   i  are, in turn, in fluid communication with second concentrator inlet port  103   j  through the first internal fluid path of fluid valve  101  (in the first valve configuration). Accordingly, because inlet opening  92   b  of second analyte concentrator  90   b  is in fluid communication with concentrator inlet port  103   j,  output line  76  is in fluid communication with second analyte concentrator  90   b  in the first valve configuration. 
     In operation in the first valve configuration, an analyte sample ( 52 ) passing through analyte input line  54  is introduced into fluid valve  101  at first fluid inlet port  103   a,  passes (fluidly) within the first internal fluid valve flow path of fluid valve  101  to first concentrator inlet port  103   b,  and then exits fluid valve  101  through first concentrator inlet port  103   b  to pass (fluidly), via an optional valve line  101   a,  into analyte concentrator  90   a  via inlet opening  92   a.  As described above, analyte molecules disposed in the analyte sample ( 52 ) are retained in analyte concentrator  90   a  by means of one or more analyte retention mechanisms ( 91 ). The substantially analyte-free sample effluent (i.e., un-retained fluid sample and/or flow-through) passes (fluidly) out of first analyte concentrator  90   a  via outlet opening  94   a.  The effluent is then introduced into fluid valve  101  at first concentrator outlet port  103   e  by means of an optional valve line  101   b.  The effluent then passes (fluidly) within the first internal fluid valve flow path of fluid valve  101  to first fluid outlet port  103   f,  and then exits fluid valve  101  through fluid outlet port  103   f  to pass (fluidly) through effluent output line  62  (e.g., to eluent generation module  64  as depicted in  FIG. 2 ). Those skilled in the art will appreciate that an optional wash fluid can also be introduced through input line  54 . 
     Continuing in the first valve configuration, a fluid eluent (e.g., a substantially analyte-free eluent generated of and/or from the substantially analyte-free effluent of and/or from first concentrator column  90   a  in an eluent generation module) passing through eluent line  70  is introduced into fluid valve  101  at second fluid inlet port  103   h.  The eluent then passes (fluidly) within the first internal fluid flow path of fluid valve  101  (in the first valve configuration) to second fluid outlet port  103   g,  and then exits fluid valve  101  through second fluid outlet port  103   g  and passes (fluidly) through an optional valve line  101   c  to opening  94   b  of concentrator column  90   b.  The eluent elutes at least a portion of the one or more analyte molecules of interest retained therein (as described below in relation to  FIG. 6B ), which is discharged from column  90   b  through opening  92   b.  The eluted analyte is introduced into fluid valve  101  at port  103   j.  The first internal fluid flow path of fluid valve  101  also includes a fluid connection between ports  103   j,    103   i,    103   d,  and  103   c.  Accordingly, the eluted analyte sample introduced into fluid valve  101  via port  103   j  (in the first valve configuration) passes directly to port  103   c  and out of fluid valve  101  via output line  76 . 
     However, as illustrated in  FIG. 6B , in the second valve configuration, the analyte sample ( 52 ) passing through analyte input line  54  and introduced into fluid valve  101  at first fluid inlet port  103   a,  passes (fluidly) within the second internal fluid valve flow path of fluid valve  101  to second concentrator inlet port  103   j,  and then exits fluid valve  101  through second concentrator inlet port  103   j  to pass (fluidly), via optional valve line  101   d,  into analyte concentrator  90   b  via inlet opening  92   b.  As described above, analyte molecules disposed in the analyte sample ( 52 ) are retained in analyte concentrator  90   b  by means of one or more analyte retention mechanisms ( 91 ). The substantially analyte-free sample effluent (i.e., un-retained fluid sample and/or flow-through) passes (fluidly) out of second analyte concentrator  90   b  via outlet opening  94   b.  The effluent is then introduced into fluid valve  101  at second concentrator outlet port  103   g  by means of an optional valve line  101   c.  The effluent then passes (fluidly) within the second internal fluid valve flow path of fluid valve  101  (in the second valve configuration) to first fluid outlet port  103   f,  and then exits fluid valve  101  through fluid outlet port  103   f  to pass (fluidly) through effluent output line  62  (e.g., to eluent generation module  64  as depicted in  FIG. 2 ). 
     Continuing in the second valve configuration, a fluid eluent (e.g., substantially analyte-free eluent generated of and/or from the substantially analyte-free effluent of and/or from second concentrator column  90   b  in an eluent generation module) passing through eluent line  70  is introduced into fluid valve  101  at second fluid inlet port  103   h,  which is in fluid communication with opening  94   a  of first analyte concentrator  90   a  via ports  103   i,    103   d,  and  103   e,  as well as optional valve line  101   b.  Accordingly, the substantially analyte-free eluent exits fluid valve  101  via port  103   e  and is introduced into analyte concentrator  90   a  (in a direction opposite the flow of the analyte sample ( 52 ) into analyte concentrator  90   a  (i.e., in a counter-current direction) as described above in relation to  FIG. 6A ). The substantially analyte-free eluent can be chemically configured to elute the analyte molecules retained in analyte concentrator  90   a  (or by the analyte retention mechanism ( 91 ) thereof). 
     The (concentrated) eluted analyte sample exits analyte concentrator  90   a  via opening  92   a  and is introduced into fluid valve  101  at port  103   b.  The concentrated, eluted analyte sample then passes to second fluid outlet port  103   c  via the second internal fluid flow path of fluid valve  101  (in the second valve configuration), and then exits fluid valve  101  through second fluid outlet port  103   c  to pass (fluidly) through output line  76  (e.g., to analyte detection module  78  as depicted in  FIG. 5B ). 
     As illustrated in  FIG. 8 , analyte detection module  78  can comprise a chromatography member  158 , a suppressing member  160 , a conductivity detector  170 , and/or a data management member  180  in one or more embodiments. It will be appreciated, however, that analyte detection module  78  need not include each of the aforementioned components and/or can include additional components as known in the art. Illustratively, in operation, the eluted, concentrated analyte can pass via line  76  (or sub-line  76   a  thereof, see  FIG. 2 ) into chromatography member  158 . Chromatography member  158  can comprise, for example, an ion exchange (separation) column, such as an anion exchange or cation exchange column in certain embodiments. Such chromatography (separation) columns can be used to separate (ionic) material eluted off of the analyte concentrator (column)  90 . 
     The eluted, concentrated (and optionally separated) analyte sample can pass via line  112  from chromatography member  158  to suppressing member  160  of analyte detection module  78  in at least one embodiment. In some embodiments, a suppressing member (i.e., “suppressor”) can be used to suppress the conductivity of the eluent and increase the conductivity of the (fully) dissociated analyte (e.g., before the analyte sample is introduced into a detection component, such as conductivity detector  170 ). Illustratively, suppressing member  160  can be or comprise an electrolytic suppressor, eluent suppressor, electrolytic eluent suppressor, electrolytically regenerated suppressor, etc. as known in the art. Suppressing member  160  can also function and/or be used to suppress the conductivity of the eluent and increase the conductivity of the fully dissociated analyte. For instance, in some embodiments, suppressing member  160  can comprise a suppressing element  160   a  or other mechanism suitable for suppressing the conductivity of the eluent in the fluid sample and increasing the conductivity of the fully dissociated analyte in the fluid sample. 
     The eluted, concentrated analyte can also pass via line  112   a  from suppressing member  160  into conductivity detector  170  of analyte detection module  78  in at least one embodiment. Conductivity detector  170  can comprise a conductivity cell  170   a  or other mechanism suitable for measuring the conductivity of the fluid sample. 
     In some embodiments, conductivity detector  170  can communicate (e.g., wirelessly and/or via physical (wired) connection  112   c ) with data management member  180 . Data management member  180  can comprise a computer-implemented software program  180   a  in certain embodiments. The software program and be stored on a computer-readable media  180   b  in one or more embodiments. Accordingly, data management member  180  can also include a (general or special purpose) computer  180   c  configured to operate the software program and/or execute the computer-readable media. 
     In addition, a fluid recycling line  112   b  can form an additional connection between suppressing member  160  and conductivity detector  170 . Accordingly, in a recycle mode, the measured sample can be introduced back into suppressing member  160  to regenerate the suppressing member  160 . The sample can then exit suppressing member  160  via line  86  as described above. 
     As illustrated in  FIG. 7 , eluent generation module  64  can comprise a pump  120 , an eluent generation component  130 , a trap column  140  and/or a de-gasser  150 . In operation, a substantially analyte-free effluent of and/or (discharged) from an analyte concentrator assembly and/or analyte concentrator column thereof passes via effluent line  62  and pump  120  into eluent generation component  130  by means of optional line  110   a.  Pump  120  can b e or comprise a high-pressure, non-metallic fluid pump in one or more embodiments. 
     Eluent generation component  130  can include an anode  130   a,  a cathode  130   b  (disposed substantially opposite anode  130   a ), and an electrolytic chamber  130   c  disposed at least partially between anode  130   a  and cathode  130   b.  The electrolytic chamber  130   c  can include an electrolyte reservoir  130   d,  an eluent generation chamber  130   e,  and/or an ion exchange connector  130   f  (e.g., disposed between the electrolyte reservoir  130   d  and the eluent generation chamber  130   e ). In another embodiment, one of the electrodes is disposed in the electrolyte reservoir  130   d  and the other electrode is disposed in the eluent generation chamber  130   e.    
     The substantially analyte-free eluent generated in eluent generation component  130  passes via optional line  110   b  to an optional trap column  140  (e.g., configured to trap any residual contaminants in the eluent and/or to further purify the eluent). In at least one embodiment, trap column  140  can be or comprise a continuously regenerated trap column (CR-TC) as known in the art. 
     The substantially analyte-free eluent then optionally passes via optional line  110   c  into de-gasser  150 . In at least one embodiment, de-gasser  150  can comprise a gas permeable membrane  150   a  configured to remove at least some of any electrolytic gases in the eluent. 
     The substantially analyte-free eluent then passes out of eluent generation module  64  by means of (eluent) line  70  as described above. In certain embodiments, a recycling and/or regenerating fluid can enter eluent generation module  64  and/or a component thereof (e.g., de-gasser  150 ) by means of line  86  as described above. For instance, the recycling and/or regenerating fluid can aid in removing at least some of any electrolytic gases in the eluent as described above. The fluid can also be optionally routed to trap column  140  to regenerate the column. The fluid can also be discharged from eluent generation module  64  and/or a component thereof (e.g., trap column  140 ) via line  110   d  (e.g., into waste). 
     Analyte concentrator systems described herein can be operated by one or more chromatography operating platforms. Operating platforms can include one or more fluid pumps, valves, lines, and/or control software programs. For instance, CHROMELEON™ chromatography data systems is offered commercially by Thermo Fisher Scientific for controlling chromatographic processes along with other types of analytical instrumentation. 
     Reference is also made herein to an analyte sample (such as analyte sample  52 ). Such an analyte sample can comprise a fluid, such as substantially potable (drinking) water, illustratively. The sample may need to be analyzed for the presence of one or more analytes (or analyte molecules) of interest (e.g., in order to determine the level(s) of the analyte(s) therein). For instance, drinking water may need to adhere to specific (governmental) standards, such as the National Primary Drinking Water Regulations (NPDWRs or primary standards). However, the concentration of certain analytes may be difficult to detect without concentrating the analytes prior to detection. 
     Analyte concentrator assemblies, such as those described herein, can include an ionic or ion-exchange concentrator column configured to retain certain ionic molecules. For instance, a drinking water sample containing one or more ionic impurities can be introduced into the concentrator column such that the ions are retained in the column. By way of illustration, an anionic-exchange concentrator column can be configured to retain certain negatively-charged (anionic) molecules contained and/or disposed in the fluid sample. Accordingly, one or more anionic analytes may be retained in such a concentrator column, while the fluid sample effluent discharged therefrom can be substantially free of the one or more anionic analytes. Alternatively, the concentrator column can comprise a cationic concentrator column configured to retain certain positively-charged (cationic) molecules contained and/or disposed in the fluid sample. Accordingly, one or more cationic analytes may be retained in such a concentrator column, while the fluid sample effluent discharged therefrom can be substantially free of the one or more cationic analytes. 
     By way of illustration, to accomplish such an elution, the eluent (such as that generated in an eluent generation module of and/or from the substantially analyte-free effluent, as described herein) can include chemical constituents that are more likely to be retained by the concentrator column than is the analyte. Accordingly, the analyte molecules of interest are released as the chemical constituents of eluent are retained instead. 
     The eluent may be generated manually, by mixing an eluent solution, or automatically, by an eluent generator. The eluent generator can process an input fluid to produce an eluent therefrom. For instance, the eluent generator can process the substantially analyte-free effluent (e.g., by exchanging molecules disposed therein with molecules adapted for eluting the retained analyte(s) from the concentrator column). 
     Accordingly, various embodiments of the present disclosure overcome or solve one or more of the foregoing or other problems in the art, by providing a substantially analyte-free eluent, generated of and/or from the substantially analyte-free effluent of and/or (discharged) from an analyte concentrator assembly and/or analyte concentrator column thereof, and configured for eluting analyte(s) retained in the same or different analyte concentrator assembly and/or analyte concentrator column thereof. The analyte sample effluent can also be used as wash fluid (for washing un-retained fluid sample from the system) in certain embodiments. 
     The foregoing detailed description makes reference to specific exemplary embodiments. However, it will be appreciated that various modifications and changes can be made without departing from the scope contemplated herein and as set forth in the appended claims. More specifically, while illustrative exemplary embodiments in this disclosure have been more particularly described, the present disclosure is not limited to these embodiments, but includes any and all embodiments having modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the foregoing detailed description. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the foregoing detailed description, which examples are to be construed as non-exclusive. 
     Moreover, any steps recited in any method or process described herein and/or recited in the claims may be executed in any order and are not necessarily limited to the order presented in the claims, unless otherwise stated (explicitly or implicitly) in the claims. Accordingly, the scope of the invention should be determined solely by the appended claims and their legal equivalents, rather than by the descriptions and examples given above. 
     It will also be appreciated that various features, members, elements, parts, and/or portions of certain embodiments of the present invention are compatible with and/or can be combined with, included in, and/or incorporated into other embodiments of the present invention. Thus, disclosure a certain features, members, elements, parts, and/or portions relative to a specific embodiment of the present invention should not be construed as limiting application or inclusion of said features, members, elements, parts, and/or portions to the specific embodiment. Rather, it will be appreciated that other embodiments can also include said features, members, elements, parts, and/or portions without necessarily departing from the scope of the present invention. Likewise, certain embodiments can include fewer features than those disclosed in specific examples without necessarily departing from the scope of this disclosure. 
     In addition, the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.