Field-Flow Fractionator

Abstract

The present disclosure describes a field flow fractionator comprising: (1) a top plate assembly including a first non-corrosive material, at least three fluid fittings machined in the first non-corrosive material, a top cavity machined in the first non-corrosive material, and at least one top plate O-ring configured to form the horizontal geometry of a separation channel; (2) a membrane; and (3) a bottom plate assembly including a second non-corrosive material, a bottom cavity machined in the second non-corrosive material, a frit configured to be disposed in the bottom cavity, and at least one bottom plate O-ring configured to seal the bottom plate assembly to the top plate assembly, wherein a top surface of the second non-corrosive material and a top surface of the frit are machined to be coplanar; and (4) the top plate assembly, membrane, and bottom assembly define a separation channel.

Description

[Technical Field]

[0001] (Priority Claim) This application claims the benefit of the earlier filing date of U.S. Patent Application No. 17 / 979,749, filed November 2, 2022, and entitled "Field Flow Fractionator," the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The present disclosure relates to field-flow fractionators, and more particularly to field-flow fractionators. Summary of the Invention

[0003] The present disclosure provides a field flow fractionator (FFF) comprising: (1) a top plate assembly including: (a) a first non-corrosive material; (b) at least three fluid fittings machined in the first non-corrosive material; (c) a top cavity machined in the first non-corrosive material; and (d) at least one top plate O-ring configured to form a horizontal geometry of a separation channel; (2) a membrane; and (3) a bottom plate assembly including: (a) a second non-corrosive material; (b) a bottom cavity machined in the second non-corrosive material; and (c) a membrane disposed in the bottom cavity. and (d) a bottom plate assembly including at least one bottom plate O-ring configured to seal the bottom plate assembly to the top plate assembly, wherein an upper surface of the second non-corrosive material and an upper surface of the frit are machined to be flush with each other; and (4) the top plate assembly, membrane, and bottom assembly define a separation channel, and the top plate assembly is configured to be in direct contact with the bottom plate assembly upon assembly of the field-flow fractionator. [Brief explanation of the drawings]

[0004] [Figure 1] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 2A] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 2B] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 2C] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 2D] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 3A] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 3B] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 3C] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 3D] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 4A] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 4B] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 4C] 1 depicts a field-flow fractionator according to an exemplary embodiment. [Figure 5] 1 depicts a field-flow fractionator according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0005] The present disclosure provides a field-flow fractionator (FFF) comprising: (1) a top plate assembly including: (a) a first non-corrosive material; (b) at least three fluid fittings machined in the first non-corrosive material; (c) a top cavity machined in the first non-corrosive material; and (d) at least one top plate O-ring configured to form a horizontal geometry of a separation channel; (2) a membrane; and (3) a bottom plate assembly including: (a) a second non-corrosive material; (b) a bottom cavity machined in the second non-corrosive material; and (c) a membrane in the bottom cavity. (d) a bottom plate assembly including at least one bottom plate O-ring configured to seal the bottom plate assembly against the top plate assembly, wherein the top surface of the second non-corrosive material is machined to be flush with the top surface of the frit; and (4) the top plate assembly, membrane, and bottom assembly define a separation channel, and the top plate assembly is configured to be in direct contact with the bottom plate assembly during assembly of the field flow fractionator. In embodiments, the at least three fluid couplings include an inlet coupling, an outlet coupling, and a cross-flow coupling. In embodiments, the top cavity has a depth of 400 μm to 650 μm. In embodiments, the top plate assembly includes a dovetail O-ring groove configured to hold the top plate O-ring. In embodiments, the membrane has a thickness of approximately 150 μm. In embodiments, the channel height is the difference between the depth of the top cavity and the thickness of the membrane.

[0006] In embodiments, the bottom plate O-ring is configured to prevent leakage from the field-flow fractionator. In embodiments, the top surface of the second non-corrosive material and the top surface of the frit are machined to be flush by at least one of surface grinding, sanding, and lapping. In embodiments, the top plate assembly directly contacts the bottom plate assembly during assembly of the field-flow fractionator, eliminating the need for a torque wrench to assemble the field-flow fractionator.

[0007] definition particle Particles can be components of an aliquot of a liquid sample. Such particles can be molecules of various types and sizes, nanoparticles, virus-like particles, liposomes, emulsions, bacteria, and colloids. These particles can range in size from nanometers to microns.

[0008] Analysis of polymer or particle species in solution Analysis of macromolecular or particle species in solution can be accomplished by preparing the sample in an appropriate solvent and then injecting an aliquot into a separation system such as a liquid chromatography (LC) column or field flow fractionation (FFF) channel, where different particle species contained within the sample are separated into their various components. Once separated, typically based on size, mass, or column affinity, the sample can be subjected to analysis by light scattering, refractive index, ultraviolet absorbance, electrophoretic mobility, and viscosity response.

[0009] Field-flow fractionation Separation of particles in solution by field-flow fractionation (FFF) was studied and extensively developed by J.C. Giddings in the early 1960s. The basis of these techniques is the interaction of a sample confined to a channel with an applied electric field applied perpendicular to the direction of flow. Among the techniques currently attracting attention is cross-flow FFF, often called symmetric flow (SFlFFF), in which the applied electric field is achieved by introducing a secondary flow perpendicular to the sample fluid in the channel. Several variations of this technique exist, including asymmetric flow FFF (i.e., A4F) and hollow fiber (H4F) flow separation.

[0010] Other FFF techniques include (i) sedimentation FFF (SdFFF), in which gravity / centrifugal cross forces are applied perpendicular to the direction of channel flow; (ii) electrical FFF (EFFF), in which an electric field is applied perpendicular to the channel flow; and (ii) thermal FFF (ThFFF), in which a temperature gradient is applied laterally.

[0011] Common to all these methods of field-flow fractionation is a fluid or mobile phase into which an aliquot of sample is injected, where separation into component fractions is achieved by the application of a cross-field. Many field-flow fractionators allow for control and variation of the strength of the cross-field, which may be an electric field, cross-flow, thermal gradient, or other variable electric field, as the sample aliquot flows down the channel.

[0012] Symmetrical Cross-Flow Fractionator (SFlFFF) To illustrate particle separation by field-flow fractionation, a simplification of perhaps the simplest system, SFlFFF, will be described. The sample is injected into the inlet port along with the spent mobile phase. The sample is allowed to undergo a so-called "relaxation period," during which no channel flow is applied, but larger particles are pushed further down the channel height than smaller particles by the constantly applied cross-flow. Once channel flow is resumed, an aliquot of the sample resides in the region of the channel flow cross-section near the center of the channel height where channel flow is fastest, and thus begins to undergo non-steric separation while small particles migrate down the length of the channel ahead of larger particles. As the cross-flow velocity is increased, separation of all species continues, while larger fractions begin to lag further behind their smaller-sized companions. After exiting the channel through the outlet port, the fractionated sample can be analyzed using a variety of detectors.

[0013] Asymmetric flow FFF (A4F) Asymmetric flow FFF (A4F) is generally considered a variation of the previously developed SFlFFF. The A4F channel assembly may include (1) a bottom assembly structure 150 holding a liquid-permeable frit surrounded by a sealing O-ring, (2) a permeable membrane overlying the frit, (3) a spacer approximately 75 μm to 800 μm thick with a cavity cut into it, and (4) a top assembly structure generally holding a transparent plate of polycarbonate material or glass.

[0014] The resulting sandwich is held together with bolts or other means, such as applying sufficient pressure to keep the channels sealed against leaks. Such pressure may be applied by a vice or clamping mechanism, as long as it provides a relatively uniform pressure across the channel assembly to prevent leaks. A generally coffin-shaped or tapered cavity within the spacer serves as the channel where separation occurs. The upper assembly structure typically includes three holes, called ports, that penetrate the top plate and are centered above the channel, allowing fittings to be attached thereto. These ports are: (a) a mobile phase inlet port located near the beginning of the channel through which the carrier liquid, or mobile phase, is pumped; (b) a sample port downstream of the inlet port, where an aliquot of the sample to be separated is introduced into the channel and focused below; and (c) an outlet port where the fractionated aliquot exits the channel near the end of the cavity.

[0015] Field-flow fractionation (FFF) systems are commonly used to fractionate particles and molecules by applying an electric field to a fluid sample so that particles accumulate against an accumulation wall. In asymmetric flow FFF (A4F), the sample-containing fluid passes through a semipermeable membrane, which allows the solvent to pass through but retains the sample. The membrane surface forms the accumulation wall, and the flow through the membrane is called crossflow. The Stokes force on the particles causes a flux that pushes the sample toward the membrane. Diffusion of high concentrations near the membrane generates an upward flux that counteracts the Stokes force. The balance of these fluxes results in an exponential concentration profile that is maximum at the membrane surface and decays in the bulk. Particles of different sizes have different balances between these two fluxes. Larger particles have a higher Stokes flux and a smaller diffusion flux compared to smaller particles, resulting in a shorter exponential decay length. Both large and small particles have a maximum concentration at the wall, but smaller particles protrude further into the bulk.

[0016] During the fractionation process, a channel flow parallel to the plane is applied. Pico-cell flow between parallel plates creates velocity shear at the boundary. Smaller particles that protrude further into the bulk move downstream more rapidly than larger particles and therefore elute first, followed by progressively larger particles. This is the well-known FFF mechanism.

[0017] Current Technology Field-flow fractionation systems have achieved moderate commercial success in recent years. The most common variant of FFF is asymmetric flow field-flow fractionation (AF4). However, the AF4 market is insignificant compared to competing fractionation techniques such as size exclusion chromatography (SEC). There are many reasons for this discrepancy. One reason is that modern AF4 systems are substantially more expensive than comparable SEC instruments. Another reason is that SEC is a very mature technology and is very easy to operate. In contrast, FFF systems are more difficult to operate and require more user intervention.

[0018] For example, in the early days of SEC, users routinely purchased empty columns and manually packed them. As the market matured, prepacked columns became consumables. Users ordered columns from a catalog, connected the column to their chromatograph, and began running samples. The convenience and simplicity of prepacked columns has relegated manual packing to the realm of academic research. Furthermore, because columns are made in factories dedicated to their construction, their quality is typically much higher than that achievable with manual packing.

[0019] In some ways, the AF4 market is still at a developmental stage comparable to that of SEC, where manually packed columns were the norm. To use an AF4 channel, users must disassemble the channel by removing numerous bolts, clean the interior, install a new membrane, and painstakingly reassemble the channel assembly. The assembly procedure involves tightening the star-shaped bolts to a specific torque using a torque wrench. Next, users must flush out air bubbles and check for leaks. Finally, separation membranes often need to be conditioned by injecting samples that bind to nonspecific binding sites to prevent subsequent samples from adhering to the membrane and reducing mass recovery.

[0020] In particular, conventional variable height channels (VHCs) for FFFs use separate spacers to set the channel height and define the horizontal extent of the channel. In FFFs with VHCs, the top plate presses against the spacers, which press against the membrane, which in turn presses against the frit. VHCs require careful assembly using a torque wrench to ensure that the top of the channel is parallel to the membrane and frit that form the bottom. Incorrect torque can damage or crush the frit, or the channel can leak. Additionally, VHCs often require replacement of the spacers and membrane. Furthermore, conventional channel designs (e.g., VHCs) have some variability in spacer thickness. Because performance is sensitively dependent on channel thickness, variability in channel thickness directly translates to performance variability. Furthermore, because VHCs define the horizontal extent of the channel with notches in the spacers, VHC assembly can crush the membrane during assembly. Furthermore, the fragile membrane can break near its edges.

[0021] In existing FFFs, the frit is pressed into a flat plastic top plate. Because the frit has an awkward shape (similar to a baseball), it is difficult to position the frit without leaking solvent around it. Therefore, a field-flow fractionator is needed.

[0022] In embodiments, Figures 1, 2A, 2B, 2C, 2D, 3A, 3B, 3C, 3D, 4A, 4B, 4C and 5 depict field-flow fractionators.

[0023] In embodiments, Figures 2A, 2C, and 2D depict the top plate assembly, where the O-ring defines the channel geometry, and the membrane clearance / top cavity depth minus the membrane thickness is the channel spacing. For example, a nominal membrane thickness of 150 μm and a top plate channel depth of 500 μm corresponds to an effective FFF channel depth of 500-150=350 μm. In embodiments, the membrane clearance / top cavity is a shallow recess that ensures that only the O-ring contacts the membrane, thereby preventing any hard surfaces from crushing the membrane and rupturing the delicate surfaces. In embodiments, the bottom O-ring seals against the top plate contact surface, thereby sealing the channel against leakage from the FFF.

[0024] 3D depicts the bottom plate assembly with the frit installed. In an embodiment, the bottom plate and frit surfaces are polished flat when assembled so that they are exactly flush with each other, with the contact area of ​​the bottom plate being where the bottom O-ring seals.

[0025] Top Plate Assembly In a further embodiment, the top plate assembly further includes a recessed cavity, as depicted in FIG. 2A. In an embodiment, the recessed cavity provides clearance for the membrane to allow the membrane to avoid being crushed during assembly of the FFF. In an embodiment, the recessed cavity is a dovetail O-ring groove, as depicted in FIG. 2B. In an embodiment, the top plate assembly includes at least one window. In an embodiment, the at least one window provides an optical channel to allow verification of proper operation of the channel.

[0026] Alignment In a further embodiment, as depicted in Figures 1, 2A, 2C, 2D, 3A, 3B, 3B, 3C, and 3D, the bottom plate assembly further includes at least two pins and the top plate assembly further includes at least two holes, where the at least two pins are configured to mate with the at least two holes, thereby aligning the bottom plate assembly with the top plate assembly. In a further embodiment, as depicted in Figures 1, 2A, 2C, 2D, 3A, 3B, 3B, 3C, and 3D, the top plate assembly further includes at least two clearance holes configured to mate with the at least two flat-bottom bolts, and the bottom plate assembly further includes at least two screw holes configured to mate with the at least two flat-bottom bolts, thereby clamping the top plate assembly with the bottom plate assembly.

[0027] In a further embodiment, the top plate assembly further includes at least two conical countersinks configured to mate with at least two conical screws, thereby aligning the top plate assembly with the bottom plate assembly, as depicted in Figures 4A, 4B, and 4C. In an embodiment, the at least two conical screws are flat head screws.

[0028] In an embodiment, Figure 4B depicts the top of a completed FFF assembly. In an embodiment, the top and bottom plate assemblies can be aligned in two ways. In an embodiment, in the first way shown in Figure 4B, the top plate assembly has a countersink feature that receives a flat top screw, and the cone / cone hole on the top plate assembly automatically aligns with the cone / cone screw, simultaneously aligning and securing the top plate assembly to the bottom plate assembly.

[0029] In a further embodiment, the bottom plate assembly further includes at least two pins and the top plate assembly further includes at least one hole and at least one slot, an axis of the at least one slot aligned with the center of the at least one hole, and the at least two pins configured to mate with the at least one hole and the at least one slot, thereby aligning the bottom plate assembly with the top plate assembly. In an embodiment, the at least one slot has a tight tolerance along the axis of the at least one slot.

[0030] In an embodiment, the FFF has at least two pins on either the top or bottom plate assembly and two receiving holes on the other plate. If the FFF is an electrical FFF with electrical channels, this method of having pins can be used with insulating pins because the top and bottom plate assemblies must be electrically isolated. In an embodiment, instead of two pins and two holes, the FFF can use two pins, one hole, and one slot to align the bottom and top plate assemblies. In an embodiment, FIG. 4C depicts an FHC assembled using flat-head screws.

[0031] Bolts and Latches In a further embodiment, the field-flow fractionator further includes bolts for sealing the channels and positioning the bottom surface of the top plate assembly, the spacer, the membrane, and the top-bottom plate assembly parallel to one another. In an embodiment, Figure 1 depicts the field-flow fractionator and the bolts. In a further embodiment, the field-flow fractionator further includes washers configured to electrically insulate the bolts from the top plate assembly.

[0032] In a further embodiment, the field-flow fractionator further comprises a spring latch for sealing the channel and positioning the bottom surface of the top plate assembly, the spacer, the membrane, and the top-bottom plate assembly parallel to one another.

[0033] Sensor In a further embodiment, the field-flow fractionator further includes a memory configured to store data related to the field-flow fractionator, the data including at least one of channel geometry, manufacturing date, membrane chemistry, build date, first wet date, number of injections, number of solvents used, type of solvent used, and number of samples fractionated. In an embodiment, the memory is a radio frequency identification chip (RFID chip). For example, the channel geometry can describe the length, width, and / or thickness of the channel. Also, for example, the manufacturing date can describe the date the field-flow fractionator was manufactured. As a further example, the membrane chemistry can describe the membrane type, membrane porosity, and membrane molecular weight cutoff. For example, the build date can describe the date the field-flow fractionator was constructed.

[0034] Also, for example, first wet date can describe the date the field-flow fractionator was first wetted. As a further example, number of injections can describe the number of injections introduced into the field-flow fractionator. For example, number of solvents used can describe the number of solvents used in the field-flow fractionator. Also, for example, type of solvent used can describe the type of solvent used in the field-flow fractionator. As a further example, number of samples fractionated can describe the number of samples fractionated by the field-flow fractionator.

[0035] In a further embodiment, the field flow fractionator further includes at least one environmental sensor configured to measure at least one of the temperature of the solvent flowing through the channel, the pH value of the solvent flowing through the channel, and the conductivity value of the solvent flowing through the channel. In a further embodiment, the field flow fractionator further includes an assembly sensor configured to detect the assembly date of the field flow fractionator. For example, the assembly sensor may include a Hall effect sensor on one side of the assembly sensor and a magnet on the other side of the assembly sensor. Also, for example, the assembly sensor may be a microswitch / button that can be pressed during assembly of the field flow fractionator. As another example, the assembly sensor may be an electrical circuit having an electrical circuit path that is completed during assembly of the field flow fractionator. Information from the assembly sensor can be used to limit the number of uses of the field flow fractionator for quality control purposes due to aging of the field flow fractionator through use.

[0036] Fixed height dispersion inlet channel In embodiments, as depicted in FIG. 5 , a field-flow fractionator includes a fixed-height dispersion inlet channel with a pocket in the upper plate / top plate assembly into which a metal frit is welded. In embodiments, flow through this metal frit acts as a flow distributor that forces the sample against the separation membrane, acting as a "frit inlet" system. In embodiments, the metal frit is welded in place, thereby preventing the sample from bypassing the metal frit. In embodiments, the fixed-height dispersion inlet channel has no spacers, no metal-to-metal contacts, eliminates the need for a torque wrench, and has lower consumable costs, while also having simplified operation of the dispersion inlet channel through the metal frit.

[0037] (Example) In embodiments, FFF / AF4 channels can be mass-produced in such a way that they can be considered consumables, like catalog SEC columns. The channels are assembled and tested in the factory, relieving users of labor-intensive assembly, leak testing, and membrane conditioning steps. Because the channels are consumable elements, the design can be greatly simplified by using molded parts that are assembled with inseparable techniques, such as adhesive bonding, overmolding, or heat and ultrasonic welding. This eliminates the need for O-rings, spacers, and fasteners that must be adjusted to specific torque settings.

[0038] This disclosure describes a fixed height channel (FHC) for FFF, which is essentially a reusable channel constructed from machined stainless steel or platinum-coated titanium for mobility channel modification. In embodiments, field-flow fractionators can offer several advantages. For example, an FFF with an FHC may be easier to assemble compared to a VHC. The FHC top plate screws directly onto the bottom plate assembly. Because the FHC has hard stops, it does not require a torque wrench, always seals, and ensures that the top and bottom of the channel are precisely parallel.

[0039] Additionally, in embodiments, an FFF with an FHC can provide lower consumable costs. For example, an FFF with an FHC only requires that the membrane be replaced. Additionally, in embodiments, an FFF with an FHC can provide superior reproducibility. For example, because an FFF with an FHC does not have a separate spacer, assembly-to-assembly performance may be superior. Additionally, in embodiments, an FFF with an FHC can use a fragile membrane. For example, because an FFF with an FHC defines the horizontal extent of the channel using an O-ring, an FFF with an FHC only compresses the membrane with a rubber O-ring, making it much less likely to be damaged.

[0040] Additionally, in embodiments, FFF with FHC may result in improved manufacturability. For example, in FFF with FHC, because the bottom plate is constructed by attaching the frit to the bottom assembly, the composite can be polished flat, ensuring that the top surfaces of the bottom assembly and the frit are precisely coplanar, and the only dimensional tolerance in the completed channel assembly is from the top plate. As a result, for example, only the channel recesses in the top plate need to be precisely machined, and the bottom plate can be considered flat.

[0041] The description of various embodiments of the present disclosure has been presented for purposes of illustration and is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used herein have been selected to explain the principles of the embodiments, practical applications or technical improvements to technology found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

Claims

1. 1. A field-flow fractionator comprising: A top plate assembly comprising: a first non-corrosive material; at least three fluid couplings machined into said first non-corrosive material; an upper cavity machined into the first non-corrosive material; and a top plate assembly comprising at least one top plate O-ring configured to define the horizontal geometry of the separation channel; A membrane and A bottom plate assembly comprising: a second non-corrosive material; a bottom cavity machined into said second non-corrosive material; a frit configured to be disposed within the bottom cavity; and a bottom plate assembly comprising at least one bottom plate O-ring configured to seal the bottom plate assembly to the top plate assembly; a top surface of the second non-corrosive material and a top surface of the frit are machined to be flush with each other; the top plate assembly, the membrane, and the bottom assembly define the separation channel; A field-flow fractionator, wherein the top plate assembly is configured to be in direct contact with the bottom plate assembly when the field-flow fractionator is assembled.

2. 10. The field-flow fractionator of claim 1, wherein the top plate assembly further comprises a recessed cavity.

3. the bottom plate assembly further comprising at least two pins; the top plate assembly further comprising at least two holes; 2. The field-flow fractionator of claim 1, wherein the at least two pins are configured to mate with the at least two holes, thereby aligning the bottom plate assembly with the top plate assembly.

4. the top plate assembly further comprising at least two clearance holes configured to mate with at least two flat-bottom bolts; the bottom plate assembly further comprising at least two threaded holes configured to mate with the at least two flat-bottom bolts; 4. The field-flow fractionator of claim 3, whereby said top plate assembly is clamped to said bottom plate assembly.

5. the top plate assembly further comprising at least two conical countersinks configured to mate with at least two conical screws; 10. The field-flow fractionator of claim 1, whereby said top plate assembly is aligned with said bottom plate assembly.

6. the bottom plate assembly further comprising at least two pins; the top plate assembly further comprising at least one hole and at least one slot; an axis of the at least one slot aligned with a center of the at least one hole; the at least two pins are configured to mate with the at least one hole and the at least one slot; 10. The field-flow fractionator of claim 1, whereby said bottom plate assembly is aligned with said top plate assembly.

7. sealing the channel; 10. The field-flow fractionator of claim 1, further comprising a bolt for positioning the bottom surface of the top plate assembly, the membrane, and the top surface of the bottom plate assembly parallel to one another.

8. 10. The field-flow fractionator of claim 1, further comprising a spring latch for sealing the channel and positioning the bottom surface of the top plate assembly, the membrane, and the top surface of the bottom plate assembly parallel to one another.

9. 6. The field-flow fractionator of claim 5, further comprising a washer configured to electrically insulate the bolt from the top plate assembly.

10. a memory configured to store data relating to the field-flow fractionator; 10. The field-flow fractionator of claim 1, wherein the data includes at least one of channel geometry, date of manufacture, membrane chemistry, date of construction, date of first wetting, number of injections, number of solvents used, type of solvent used, and number of samples fractionated.

11. 10. The field-flow fractionator of claim 1, further comprising at least one environmental sensor configured to measure at least one of a temperature of the solvent flowing through the channel, a pH value of the solvent flowing through the channel, and a conductivity value of the solvent flowing through the channel.

12. 10. The field flow fractionator of claim 1, further comprising an assembly sensor configured to detect an assembly date of the field flow fractionator.

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