Analytical device and analytical method

Abstract

To provide an analytical device and an analytical method capable of measuring an analytical object with high accuracy. [Solution] An analytical device characterized by having a flow injection system that reacts an analyte with a reagent in water and analyzes the analyte using the resulting reaction product; a membrane filtration device equipped with a microfiltration membrane or an ultrafiltration membrane; a concentration mechanism that accumulates the analyte in water within the membrane filtration device; a flushing mechanism that flows the analyte accumulated in the membrane filtration device into the flow injection system together with concentrated water from the membrane filtration device; a switching mechanism that switches between the concentration mechanism and the flushing mechanism; and a reagent injection unit that supplies the reagent to the flow injection system.

Description

[Technical Field]

[0001] The present invention relates to an analytical device and an analytical method. [Background technology]

[0002] Endotoxin (ET) is a microbial contaminant that requires strict control in pharmaceutical water and pharmaceutical manufacturing processes, and it is necessary to remove it as much as possible, and online monitoring is also required. Conventionally, the Limulus test has been mainly used to detect endotoxin, but online real-time analysis is difficult with the Limulus test.

[0003] Patent Document 1 describes a flow injection analysis (FIA) method in which a liquid-liquid mixture consisting of an organic phase and an aqueous phase is introduced into the inner tube of a double tube consisting of an inner tube made of a porous polymer membrane and an outer tube surrounding the inner tube, or into a region surrounded by the inner and outer tubes, the organic phase is separated from the aqueous phase by allowing only the organic phase to permeate the wall surface of the inner tube made of a porous polymer membrane, and the resulting organic phase is introduced into a detection unit to analyze the analyte. However, this method has problems with variations in reagent reaction efficiency and measurement accuracy, and there is a problem that the detection sensitivity is insufficient, particularly when detecting low concentrations of endotoxin.

[0004] Therefore, the inventors developed a method for detecting endotoxin online using flow injection analysis with a fluorescent reagent that specifically recognizes endotoxin and functions as a fluorescent label by binding to it (see, for example, Patent Document 2). Furthermore, they developed an analytical device that enhances the quantitative analysis by concentrating endotoxin through cross-flow filtration of water to be analyzed that contains low concentrations of endotoxin using an ultrafiltration membrane or the like (see, for example, Patent Document 3). Furthermore, a technology has been proposed for detecting fine particles in a liquid, in which the liquid is dead-end filtered through a membrane filtration system to accumulate the fine particles on the membrane, followed by recovery by backwashing (see, for example, Patent Document 4). In this technology, fine particles in the liquid are accumulated on the membrane surface by dead-end filtration using a large-area ultrafiltration membrane at a high flow rate, and the accumulated fine particles are then detached from the membrane surface by backwashing the membrane with alkaline functional water, and then recovered using a membrane filtration system for capturing fine particles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 62-280652 [Patent Document 2] Japanese Patent Publication No. 2022-011525 [Patent Document 3] Patent No. 7606197 [Patent Document 4] Patent Publication No. 2025-032796 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the lower the endotoxin concentration, the higher the concentration rate required, so a large permeate / concentrate flow rate ratio is required for sufficient concentration. The inventors discovered that in the analysis of such low-concentration endotoxins, a decrease in the amount of concentrated water causes endotoxins to adhere to the filtration membrane and become less likely to flow out. In particular, during long-term continuous operation, there was concern that endotoxins adhering to and accumulating on the membrane surface would not be sufficiently recovered, resulting in a decrease in endotoxin detection accuracy and a shortened membrane lifespan. Furthermore, when the technology described in Patent Document 4 is applied to endotoxin analysis, there was concern that recovery would be insufficient even with backwashing. Furthermore, the alkaline functional water used in backwashing may affect the physical properties of the endotoxin being detected, affecting its reactivity with reagents and making highly sensitive analysis difficult.

[0007] The present invention has been made to solve the above-mentioned problems, and provides an analytical method and an analytical device that can detect an analyte such as endotoxin at a low concentration with high accuracy. [Means for solving the problem]

[0008] To solve these problems, the inventors discovered a method that involves two steps: a concentration step in which endotoxin is concentrated in a membrane filtration device by membrane filtration, and an analysis step in which the concentrated endotoxin is sent to an analyzer for analysis. First, in the concentration step, the entire amount of the analyte is filtered, causing endotoxin to accumulate in the membrane filtration device. Next, in the analysis step, flushing is performed to flush the accumulated endotoxin out of the membrane filtration device. In this way, by combining accumulation and flushing, endotoxin attached to the filtration membrane can be flushed out of the membrane filtration device, making it possible to measure highly concentrated analytes with high accuracy.

[0009] The present invention has been made based on the above-mentioned studies, and embodiments of the present invention have the following configurations. [1] A flow injection system that reacts an analyte with a reagent in water and analyzes the analyte using the reaction product produced; A membrane filtration device equipped with a microfiltration membrane or an ultrafiltration membrane; a concentration mechanism for accumulating the analyte in the water within the membrane filtration device; a flushing mechanism that flushes the analyte accumulated in the membrane filtration device into the flow injection system together with the concentrated water of the membrane filtration device; a switching mechanism for switching between the concentration mechanism and the flushing mechanism; a reagent injection unit that supplies the reagent to the flow injection system; An analytical device comprising: [2] The analytical device according to [1], wherein the concentration mechanism performs dead-end filtration using the membrane filtration device. [3] The analytical device according to [1], wherein the flushing mechanism causes the entire amount of water supplied to the membrane filtration device to flow from the concentration side to the flow injection system. [4] The analytical device according to [1], wherein the flushing mechanism causes 50% or more of the feed water of the membrane filtration device to flow into the flow injection system as concentrated water. [5] The analyzer according to [4], wherein the reagent injection unit injects the reagent into the reagent line. [6] The analytical device according to [1], wherein the flushing mechanism includes a backwashing mechanism that supplies water from the permeation side of the membrane filtration device and causes the analyte to flow out from the concentration side of the membrane filtration device. [7] The analytical device according to any one of [1] to [6], wherein the flow injection system is capable of quantitatively analyzing the analyte. [8] An analytical method for analyzing an analyte using a reaction product produced by reacting the analyte with a reagent in water, comprising: a concentration step of accumulating the analyte on one or more filtration membranes selected from a microfiltration membrane and an ultrafiltration membrane; an analyzing step of flowing the reagent into the flow injection system while flowing the accumulated analyte together with the concentrated water from the filtration membrane into the flow injection system. [9] The analytical method according to [8], wherein in the concentration step, total filtration is performed using the filtration membrane.

[10] The analytical method described in [8], wherein the reagent is flowed into the flow injection system together with the permeate of the filtration membrane.

[11] The analytical method according to [8], wherein in the analysis step, the entire amount of water supplied to the filtration membrane is passed through the flow injection system as the concentrated water.

[12] The analytical method according to any one of [8] to

[11] , wherein the analytical method is capable of quantitatively analyzing the analyte. The symbol "~" indicates a range of values ​​including the values ​​before and after it. [Effects of the Invention]

[0010] According to the analytical device and analytical method of the present invention, it is possible to measure an analyte with high accuracy. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an analysis device according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an analysis device according to another embodiment of the present invention. [Figure 3] FIG. 10 is a diagram illustrating an analysis device according to another embodiment of the present invention. [Figure 4] FIG. 10 is a diagram illustrating an analysis device according to another embodiment of the present invention. [Figure 5] FIG. 10 is a diagram illustrating an analysis device according to another embodiment of the present invention. [Figure 6] FIG. 10 is a diagram illustrating an analysis device according to another embodiment of the present invention. [Figure 7] 1 is a graph showing a schematic diagram of changes in the concentration of concentrated water measured by the analyzer of the present invention and the analyzer of the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a diagram illustrating an analytical device 12 according to an embodiment of the present invention. The analytical device 12 shown in FIG. 1 analyzes bacterial-derived substances and fungi (viable bacteria themselves) contained in water to be analyzed. That is, the analytical device 12 according to this embodiment can detect the analyte in the water to be analyzed (qualitative analysis) or measure the concentration of the analyte in the water to be analyzed (quantitative analysis). The bacterial-derived substance is, for example, endotoxin, which is a lipopolysaccharide that constitutes the cell wall of gram-negative bacteria.

[0014] Examples of water to be analyzed include pharmaceutical water such as water for injection (WFI) and purified water, and water for semiconductor manufacturing such as pure water and ultrapure water. The water to be analyzed may be water collected during the manufacturing process of the pharmaceutical water or semiconductor water. The water to be analyzed can be collected from a water treatment system. Examples of water treatment systems include purified water manufacturing systems, water for injection manufacturing systems, pure water manufacturing systems for manufacturing semiconductor water, and ultrapure water manufacturing systems.

[0015] The analyzer 12 according to this embodiment has a concentration mechanism that concentrates the analyte and an analysis mechanism (flushing mechanism) that analyzes the concentrated analyte. The analyzer 12 also has a switching mechanism that switches between the concentration mechanism and the analysis mechanism. For example, the concentration mechanism and the analysis mechanism are composed of one or more valves that can be opened or closed, and one or more pipes that form the flow paths for the water to be analyzed and the flushing water. The switching mechanism is, for example, a control device that switches the flow paths by controlling the opening and closing of each valve, and the control device can switch between the concentration mechanism and the analysis mechanism.

[0016] The analyzer 12 includes a preconcentration pump 14, a membrane filtration device 16, and a pipe 18 connected to the inlet side of the membrane filtration device 16. The preconcentration pump 14 is provided in the pipe 18, and the water to be analyzed (feed water) is sent to the pump 14 from the water treatment system. Here, the feed water refers to the water to be analyzed that is supplied to the membrane filtration device 16. The preconcentration pump 14 pressurizes the water to be analyzed. The pressurized water to be analyzed is sent to the membrane filtration device 16 via the pipe 18. Note that, for example, when the analyzer 12 is directly attached to the sampling line of a purified water production system or an ultrapure water production system for online analysis, the preconcentration pump 14 can be omitted if the pressure in the sampling line is appropriate for sending the water to be analyzed to the downstream stage. Furthermore, if the pressure in the sampling line is higher than the appropriate pressure, a pressure reducing means such as a pressure reducing valve can be installed instead of the preconcentration pump 14. The analyzer 12 can measure the analyte online or offline, with online measurement being preferred.

[0017] The membrane filtration device 16 has an outer cylinder 20. An ultrafiltration membrane 30 or a microfiltration membrane is disposed inside the outer cylinder 20. The pore size of the ultrafiltration membrane 30 is large enough to capture bacteria-derived substances as the analyte, and the molecular weight cutoff is generally 1 kDa to 100 kDa. The pore size of the microfiltration membrane is large enough to capture bacteria as the analyte, and the pore size is generally 0.1 μm to 0.5 μm. Note that a microfiltration membrane may be used instead of the ultrafiltration membrane. As the ultrafiltration membrane or microfiltration membrane, a membrane with a removal rate of the analyte of 90% or more is more preferable, and a membrane with a removal rate of 95% or more is even more preferable.

[0018] The ultrafiltration membrane 30 can be made of any material suitable for ultrafiltration membranes, including, without limitation, cellulose acetate, polyacrylonitrile, polysulfone, polyethersulfone, modified polyethersulfone, and polyvinylidene fluoride. Polyacrylonitrile, polysulfone, polyethersulfone, modified polyethersulfone, and polyvinylidene fluoride are preferred materials for the ultrafiltration membrane 30. Modified polyethersulfone is particularly preferred. Because modified polyethersulfone is highly hydrophilic, it facilitates the removal of particles adsorbed on the membrane surface of the ultrafiltration membrane 30. This makes it suitable for easily discharging particles accumulated in the concentration step described below from the ultrafiltration membrane 30 in the subsequent analysis step. The pore size of the ultrafiltration membrane 30 used in the filtration device 16 is large enough to capture particles; for example, the molecular weight cutoff is preferably in the range of 1 kDa to 100 kDa. Furthermore, the ultrafiltration membrane 30 is typically hollow fiber. The effective membrane area of ​​the ultrafiltration membrane 30 is 100 mm 2 More than 1000mm 2 The following ranges are preferred. This facilitates measurement of the endotoxin concentration in a relatively small amount of feed water, as described below. Although the reason is not clear, endotoxin tends to peel off easily from UF membranes (ultrafiltration membranes). One reason for this phenomenon is thought to be that, while microparticles are nearly spherical and have a uniform charge on their surfaces, endotoxin has an elongated shape and exhibits a biased charge at both ends.

[0019] A commercially available product can be used as the membrane filtration device 16. An example of a commercially available product using an ultrafiltration membrane is MIDIKROS (trade name) MPES (modified polyethersulfone) from Repligen.

[0020] An inlet section 22 is provided at one longitudinal end of an outer cylinder 20 of the membrane filtration device 16, and an outlet section 24 is provided at the other end. Furthermore, a discharge section 26 is provided on the outer periphery of the outer cylinder 20. A piping 18 is connected to the inlet section 22. A first piping 32 is connected to the outlet section 24. One end of a discharge pipe 31 is connected to the discharge section 26. A second valve 62 is provided on the discharge pipe 31. A first valve 60 is provided in the path of the first piping 32, and further, a flow injection system 40 is connected to the first piping 32 downstream of the first valve 60.

[0021] In the membrane filtration device 16, the outlet 24 is provided on the concentrate side of the ultrafiltration membrane 30, and the concentrate from the ultrafiltration membrane 30 is sent from the outlet 24 to the first pipe 32. The discharge 26 is provided on the permeate side of the ultrafiltration membrane 30, and the permeate from the ultrafiltration membrane 30 is sent to the discharge 26.

[0022] With this configuration, the concentrated water from the membrane filtration device 16 is sent as sample water to the flow injection system 40 through the first pipe 32.

[0023] The flow injection system 40 has a sample water line and a reagent line, and a pump installed within the flow injection system 40 synchronizes the supply from the sample water line and the reagent line to mix the sample water and the reagent. A first pipe 32 for supplying the sample water constitutes the sample water line. A second pipe 34 for supplying a reagent to the flow injection system 40 is connected to the flow injection system 40, and the second pipe 34 constitutes the reagent line. A reagent injection unit 44 for injecting the reagent into the second pipe 34 is connected to the second pipe 34. The reagent injection unit 44 may, for example, include a chemical injection pump that delivers a fixed amount of reagent and a pipe that delivers the reagent delivered to the chemical injection pump to the second pipe 34. A loop pipe 70 that bypasses the reagent injection unit 44 and the second pipe 34 may be connected between the reagent injection unit 44 and the second pipe 34, allowing for switchable flow paths between a flow path directly from the reagent injection unit 44 to the second pipe 34 and a flow path from the reagent injection unit 44 to the second pipe 34 via the loop pipe 70. By sending the reagent injected into the reagent injection section 44 to the second piping 34 via the loop tube 70, the time it takes for the reagent to reach the flow injection system 40 can be delayed compared to when the reagent is injected directly from the reagent injection section 44 to the second piping 34. The amount of reagent supplied to the flow injection system 40 can be adjusted by adjusting the length of the loop tube 70.

[0024] The timing of reagent injection may be controlled by the reagent injection unit 44. For example, by taking into consideration changes in the concentration of the analyte in the sample water flowing through the analyzer 48 when analysis is performed, and controlling the injection of the reagent at the timing when the endotoxin concentration in the concentrated water is at its maximum (the endotoxin concentration peak), it is possible to achieve high analytical accuracy while reducing the amount of reagent consumed. Alternatively, the timing of reagent injection may be controlled by adjusting the length of the loop tube 70 so that the reagent is supplied between the rise of the endotoxin concentration peak and the convergence of the peak. Reagent injection may also be controlled by program control.

[0025] With these configurations, the reagent injected from the reagent injection section 44 into the second pipe 34 is sent to the flow injection system 40. Then, the sample water and the reagent react with each other in the flow injection system 40 to produce a reaction product, which is measured by a measuring device in the flow injection system 40, thereby analyzing the target of analysis.

[0026] The analyzer 12 of the embodiment includes a bypass pipe 80 that connects the path of the first pipe 32 and the path of the second pipe 34. The bypass pipe 80 is provided with a third valve 64. Note that, instead of the first valve 60 and the third valve 64, a three-way valve may be provided at the connection between the first pipe 32 and the bypass pipe 80. The first valve 60, the second valve 62, and the third valve 64 may be variable aperture valves or on-off valves, and the opening / closing or aperture may be automatically controlled by a control device or the like. The same applies to the other valves described below. Each valve may be a multi-way valve. If it is a multi-way valve, it is possible to group multiple valves that are close to each other.

[0027] Next, a description will be given of an analysis method using the analysis device 12. The analysis method of this embodiment includes a concentration step and an analysis step. First, in the concentration step, the second valve 62 is opened, the first valve 60 is closed, and the third valve 64 is opened. Then, the preconcentration pump 14 supplies the water to be analyzed to the membrane filtration device 16 via the pipe 18. In addition, ultrapure water (or water for injection, the same applies hereinafter) is supplied to the second pipe 34.

[0028] As a result, the entire amount of the water to be analyzed is filtered by the membrane filtration device 16, and the analyte contained in the water to be analyzed accumulates in the membrane filtration device 16. The permeate from the membrane filtration device 16 is discharged outside the system via the discharge pipe 31. During this time, the injection of reagent from the reagent injection unit 44 is stopped. As a result, the ultrapure water supplied to the second pipe 34 is supplied to the flow injection system 40 via the second pipe 34, the bypass pipe 80, and the first pipe 32. The flow path for the water to be analyzed, formed by the open second valve 62, the closed first valve 60, and the open third valve 64, constitutes a concentration mechanism. Note that, during the concentration step, ultrapure water is supplied to the second pipe 34, and the ultrapure water is sent from the bypass pipe 80 through the first pipe 32 to the flow injection system 40. The flow injection system 40 usually requires a start-up operation to flow a solvent before starting measurement. However, by flowing ultrapure water through the flow injection system 40 during the concentration step, the analysis step can be performed immediately after the concentration step without the start-up operation. In the concentration step, the flow rate of the concentrated water in the membrane filtration device 16 is preferably 3% or less, more preferably 1% or less, of the flow rate of the feed water, and the concentration step is more preferably dead-end filtration in which the concentrated water is not discharged. In the accumulation step, dead-end filtration enables more accurate measurement of the concentration of the analyte, but as long as the flow rate of the concentrated water is within the above-mentioned preferred range, the concentration of the analyte can be measured as accurately as in the case of dead-end filtration.

[0029] In the concentration step, the supply flow rate of the ultrapure water to be measured is preferably 10 mL / min or more and 500 mL / min or less. A more preferred range is 50 mL / min or more and 400 mL / min or less. An even more preferred range is 100 mL / min or more and 300 mL / min. The analyzer 12 of this embodiment is suitable for measurements at relatively small flow rates such as those described above, and in this case, it is more likely to exhibit excellent effects. The supply flux is preferably 0.1 mm / min to 55 mm / min, more preferably 0.5 mm / min to 40 mm / min, and even more preferably 1 mm / min to 35 mm / min.

[0030] By carrying out the concentration step for a predetermined period of time, the analyte contained in the water to be analyzed that has passed through the membrane filtration device 16 during that period is accumulated in the membrane filtration device 16. Thereafter, the analysis step is carried out. In the analysis step, while the water to be analyzed and ultrapure water are being supplied to the analyzer 12, the second valve 62 is closed, the first valve 60 is opened, and the third valve 64 is closed. As a result, the analyte accumulated in the membrane filtration device 16 during the concentration step is pushed out by the newly supplied water to be analyzed and sent to the flow injection system 40 as sample water via the first pipe 32. At the same time, the reagent injection unit 44 is operated to supply the reagent into the second pipe 34. As a result, ultrapure water containing the reagent is supplied into the flow injection system 40 as carrier water. Then, the sample water and the reagent react in the flow injection system 40, producing a reaction product, which is measured by a measuring device in the flow injection system 40, thereby analyzing the analyte. At this time, the flow path for the water to be analyzed formed by the closed second valve 62, the open first valve 60, and the closed third valve 64 constitutes a flushing mechanism.

[0031] The flow rate of the water to be analyzed flowing through the first pipe 32 in the analysis step is preferably 50% or more and 100% or less of the flow rate of the water to be analyzed supplied to the membrane filtration device 16. When the flow rate of the water to be analyzed flowing through the first pipe 32 in the analysis step is 50% or more of the flow rate of the water to be analyzed supplied to the membrane filtration device 16, the water can be supplied to the flow injection system 40 without any residual analyte accumulated in the membrane filtration device 16. When the flow rate of the water to be analyzed flowing through the first pipe 32 in the analysis step is 100% or less of the flow rate of the water to be analyzed supplied to the membrane filtration device 16, the water to be analyzed can be supplied to the flow injection system 40 without being mixed with newly supplied water to be analyzed, thereby improving the accuracy of quantitative analysis. The flow rate of the water to be analyzed supplied to the membrane filtration device can be varied between the concentration step and the analysis step. In this embodiment, by closing the valve 62 during the analysis process, the flow rate of the permeate (discharge side) is made substantially zero, or by backwashing with water that does not affect the analytical device, such as pure water, it is possible to flush most of the endotoxin concentrated on the membrane surface to the measurement side.

[0032] The flow rate of the water to be analyzed supplied to the membrane filtration device 16 in the analysis step is preferably 50% or more and 300% or less of the flow rate of the water to be analyzed in the concentration step. When the flow rate of the water to be analyzed in the analysis step is 50% or more of the flow rate of the water to be analyzed in the concentration step, the analyte accumulated in the membrane filtration device 16 can be flowed to the flow injection system 40 without being left behind. When the flow rate of the water to be analyzed in the analysis step is 300% or less of the flow rate of the water to be analyzed in the concentration step, the analyte accumulated in the membrane filtration device 16 can be flowed to the flow injection system 40 without being mixed with newly supplied water to be analyzed, thereby improving the accuracy of quantitative analysis.

[0033] The supply flow rate of the water to be analyzed can be adjusted by the discharge pressure of the preconcentration pump 14. In addition, the flux may be temporarily increased at the start of flushing (at the start of the analysis process) to promote the detachment of endotoxins accumulated on the surface of the ultrafiltration membrane 30.

[0034] The volume of the water to be analyzed supplied to the membrane filtration device 16 in the concentration step and the analysis step, and the time for each step, may be adjusted depending on the expected concentration of the analyte or the height of the concentration peak measured by the analyzer 48 in the analysis step. For example, if the endotoxin concentration is low, the period of the concentration step may be set longer, and if the endotoxin concentration is high, the period of the concentration step may be set shorter. These adjustments may also be made automatically by controlling the valves using the control device described above. Furthermore, the amount and timing of reagent addition may be adjusted appropriately depending on changes in the expected concentration of the analyte or the height of the peak concentration. This optimizes the efficiency of reagent use and improves analytical accuracy.

[0035] In an analysis method using the analyzer 12, the analyte in a predetermined amount of water to be analyzed is concentrated in a concentration process, and then the concentrated water containing the analyte at a high concentration can be flowed into the flow injection system 40 as sample water. This makes it possible to analyze low concentrations of the analyte with high accuracy. In addition, by timing the injection of the reagent from the reagent injection unit 44 to coincide with the flow of the sample water containing the analyte in the analysis process, the amount of reagent used can be reduced.

[0036] The concentration of endotoxin, which is the measurement target of this embodiment, is preferably 0.001 EU / mL or more and 1 EU / mL or less. If it is adsorbed or captured on the membrane surface in a highly dispersed state, it can be easily detached from the membrane surface. 10 When the concentration is less than 1 / mL, it is easy to maintain high dispersion in water, and the highly dispersed state is accumulated in the ultrafiltration membrane 30 in the accumulation step. In addition, the amount of endotoxin adsorbed to the membrane at this time is 8.3 × 10 per area. -13 g / cm 2 ~8×10 ―6 g / cm 2 This becomes:

[0037] As described above, the analyzer 12 according to this embodiment performs a concentration step and an analysis step in combination, thereby supplying concentrated sample water of the analyte to the flow injection system 40, thereby enabling high-precision analysis of the analyte. In addition, it is possible to analyze low-concentration analytes while reducing the amount of reagent used.

[0038] Furthermore, the analyzer 12 according to this embodiment can alternately execute the concentration process and the analysis process at predetermined time intervals or according to measurement conditions. Therefore, continuous measurements are possible by measuring the analyte concentrated in the concentration process with high accuracy in the analysis process and then transitioning back to the concentration process. The time intervals at which the processes are switched may be adjusted as appropriate depending on changes in the measurement results. Switching between these processes can be performed by controlling operations such as valve opening and closing and pump control using a switching mechanism.

[0039] Next, the flow injection system 40 will be described. The flow injection system 40 includes a pump 42, which is provided either in common with the first pipe 32 and the second pipe 34 or separately, a junction pipe 46 that joins the first pipe 32 and the second pipe 34 downstream of the pump 42, and an analyzer 48 connected to the junction pipe 46. The sample water and reagent that have passed through the pump 42 are mixed in the junction pipe 46. This causes a reaction between the analyte in the sample water and the reagent in the carrier water. The reactant of the analyte and the reagent is then sent to the analyzer 48. Because the amounts of the analyte and the reactant are correlated, the concentration of the analyte is determined by measuring the reactant with the analyzer 48.

[0040] The pump 42 is, for example, a plunger pump. In this plunger pump, a plunger reciprocates within a pump housing to pressurize and send the fluid from the upstream side to the downstream side. The pump 42 is preferably a double plunger pump having two plungers arranged in parallel. The double plunger pump is commonly provided for the first pipe 32 and the second pipe 34. The pump 42 is capable of sending the sample water and carrier water downstream in synchronized pressurization cycles. The pump 42 may be a peristaltic pump, a syringe pump, or a solenoid pump. The pump 42 is more preferably a plunger pump.

[0041] When the target of analysis is endotoxin, the fluorescent reagent described in JP 2022-011525 A, in which the fluorescent moiety and the recognition moiety are linked by a spacer, can be used as the reagent, but is not limited to this. The fluorescent reagent is activated by the reaction between endotoxin and the above-mentioned fluorescent reagent. Inside the analyzer 48, piping (not shown) and a quartz cell connected to the piping are arranged. The analyzer 48 irradiates light onto the combined water flowing through the quartz cell. This causes the activated reagent to emit fluorescence, and the analyzer 48 can measure the endotoxin concentration from the signal intensity of this fluorescence. The analyzer 48 has an outlet pipe 50 that discharges the combined water after analysis.

[0042] In the analyzer 48, the activated reagent is quantified by irradiating it with excitation light having a wavelength of, for example, 340 to 360 nm and observing the generated fluorescence having a wavelength of 440 to 520 nm. In the analyzer 48, the flow rate of the sample water is preferably 0.01 to 4.00 mL / min in order to improve measurement accuracy.

[0043] The materials of the first pipe 32, the second pipe 34, and the junction pipe 46 are not limited as long as they can carry the sample water, carrier water, and junction water, respectively. The material of the piping of the analyzer 48 is not particularly limited, but may be, for example, fused silica tubing. Fused silica tubing has extremely low reactivity with activated reagents, so using fused silica tubing enables more accurate endotoxin analysis.

[0044] FIG. 2 is a diagram illustrating an analytical apparatus 121 according to another embodiment of the present invention. In the analytical apparatus 121, a reagent is constantly flowing through the flow injection system 40 throughout the concentration and analysis steps. As shown in FIG. 2, the analytical apparatus 121 has an ultrapure water pipe 82 connected to the first pipe 32 instead of the bypass pipe 80 of the analytical apparatus 12 shown in FIG. 1, and a third valve 64 is provided on the ultrapure water pipe 82. As a result, during the concentration step, the third valve 64 is opened to send ultrapure water to the flow injection system 40 through the ultrapure water pipe 82. During the analysis step, the third valve 64 is closed to stop the supply of ultrapure water, allowing only the sample water to be sent to the flow injection system 40. Furthermore, throughout the concentration and analysis steps, a reagent is constantly sent from the reagent injector 44 to the flow injection system 40 through the second pipe 34, allowing the reagent and the sample water to be mixed.

[0045] Next, referring to Figure 3, a case where the permeate of the membrane filtration device 16 is used as carrier water will be described. Figure 3 is a diagram showing an analyzer 122 according to another embodiment of the present invention. In the analyzer 122, a discharge section 26 and a water supply section 28 are provided on the outer periphery of the outer cylinder 20 of the membrane filtration device 16. A third pipe 36 is connected to the water supply section 28. The opposite end of the third pipe 36 from the water supply section 28 is connected to a pump 42 of a flow injection system 40. A reagent injection section 44 that injects a reagent into the third pipe 36 is connected to the third pipe 36, similar to the second pipe 34 of the analyzer 12 shown in Figure 1. A loop pipe 70 that bypasses the reagent injection section 44 and the third pipe 36 may be connected between the reagent injection section 44 and the third pipe 36.

[0046] 3, in the concentration step, the second valve 62 is opened and narrowed. The first valve 60 is closed, and the third valve 64 is opened. Then, the preconcentration pump 14 supplies the water to be analyzed to the membrane filtration device 16 via the pipe 18.

[0047] As a result, the entire amount of the water to be analyzed is filtered by the membrane filtration device 16, and the analyte contained in the water to be analyzed accumulates in the membrane filtration device 16. A portion of the permeate from the membrane filtration device 16 is discharged outside the system via the discharge pipe 31, and the remainder is sent to the flow injection system 40 via the third piping 36. During this time, the injection of reagent from the reagent injection unit 44 is stopped. As a result, the permeate supplied to the third piping 36 is supplied to the flow injection system 40 via the third piping 36, the bypass piping 80, and the first piping 32. At this time, the flow path for the water to be analyzed, formed by the second valve 62 with its opening adjusted, the first valve 60 which is closed, and the third valve 64 which is open, constitutes a concentration mechanism.

[0048] The discharge structure for the permeate from the membrane filtration device 16 may have only one outlet for the permeate. For example, if the membrane filtration device 16 is not provided with the water supply unit 28 and is provided only with the discharge unit 26 as an outlet for the permeate, the third piping 36 may be connected to the discharge pipe 31 upstream of the second valve 62, so that a portion of the permeate in the concentration step is sent to the third piping 36 and flows into the flow injection system. Alternatively, if the membrane filtration device 16 is not provided with the discharge unit 26 and is provided only with the water supply unit 28 as an outlet for the permeate, the discharge pipe 31 may be connected to the pipe 36 upstream of the reagent injection unit 44 via the second valve 62, so that a portion of the permeate is discharged to the outside of the system through the discharge pipe 31.

[0049] The concentration step is carried out for a predetermined period of time, and then the analysis step is carried out. During the analysis step, while the water to be analyzed is being supplied to the analyzer 122, the second valve 62 is closed, the first valve 60 is opened, and the third valve 64 is closed. As a result, the analyte accumulated in the membrane filtration device 16 during the concentration step is pushed out by the newly supplied water to be analyzed and sent to the flow injection system 40 as sample water via the first pipe 32. The permeated water from the membrane filtration device 16 flows into the third pipe 36, and at the same time, the reagent injection unit 44 is operated to supply the reagent into the third pipe 36. The permeated water containing the reagent is then supplied as carrier water to the flow injection system 40 via the third pipe 36. At this time, the flow path for the water to be analyzed formed by the closed second valve 62, the narrowed first valve 60, and the closed third valve 64 constitutes a flushing mechanism. In the analyzer 122 of this embodiment, it is preferable to adjust the inner diameters of the first pipe 32 and the third pipe 36 so that the ratio of the concentrated water flow rate to the permeated water flow rate of the membrane filtration device 16 during the analysis step is in the range of 1 to 30. Furthermore, a flow meter may be provided near the inlet of the first pipe 32, and when the flow rates in the first pipe 32 and the third pipe 36 become similar, the detection results can be corrected using the value of the flow meter.

[0050] FIG. 4 is a diagram illustrating an analytical device 123 according to another embodiment of the present invention. In the analytical device 123, a reagent is constantly flowing through the flow injection system 40 throughout the concentration and analysis steps. As shown in FIG. 4, the analytical device 123 has a second pipe 34 connected to the first pipe 32, instead of the bypass pipe 80 of the analytical device 122 shown in FIG. 3, and a third valve 64 is provided on the second pipe 34. As a result, during the concentration step, the third valve 64 is opened to send the permeated water to the flow injection system 40 through the second pipe 34. During the analysis step, the third valve 64 is closed to stop the supply of the permeated water, thereby allowing only the concentrated sample water to be analyzed to be sent to the flow injection system 40. Furthermore, throughout the concentration and analysis steps, a reagent is constantly sent from the reagent injection unit 44 to the flow injection system 40 through the third pipe 36, allowing the reagent and the sample water to be mixed.

[0051] The discharge structure for the permeated water from the membrane filtration device 16 may have only one outlet for the permeated water. For example, if the membrane filtration device 16 does not have the water supply unit 28 and only has the discharge unit 26 as an outlet for the permeated water, the second piping 34 may be connected to the discharge pipe 31 upstream of the second valve 62, so that a portion of the permeated water in the concentration step is sent to the second piping 34 and flows into a piping flow injection system. Alternatively, if the membrane filtration device 16 does not have the discharge unit 26 and only has the water supply unit 28 as an outlet for the permeated water, the discharge pipe 31 may be connected to the second piping 34 upstream of the third valve 64 via the second valve 62, so that a portion of the permeated water is discharged to the outside through the discharge pipe 31.

[0052] Next, with reference to Figure 5, a case will be described in which water to be analyzed is supplied in the backwash direction of the membrane filtration device 16 during the analysis process, and the water to be analyzed is discharged from the concentration side. Figure 5 is a diagram showing an analyzer 124 according to another embodiment of the present invention. In the analyzer 124, the downstream side of the outlet 24 and the downstream side of the discharge section 26 of the membrane filtration device 16 have the same configuration as the analyzer 122 shown in Figure 3, and therefore components that perform the same functions are assigned the same reference numerals and redundant explanations will be omitted.

[0053] The analyzer 124 includes a fourth pipe 38 and a fifth pipe 39. One end of the fourth pipe 38 is connected to the pipe 18, and the other end is connected to the fifth pipe 39. A fourth valve 66 is provided on the fourth pipe 38. One end of the fifth pipe 39 is connected to the discharge unit 26. The permeated water can be discharged from the fifth pipe 39 to the outside of the analyzer 12. The fifth pipe 39 includes a second valve 62 downstream of the connection with the fourth pipe 38. The pipe 18 includes a fifth valve 68 downstream of the connection with the fourth pipe 38.

[0054] The discharge structure for the permeated water from the membrane filtration device 16 may have only one outlet for the permeated water. For example, if the membrane filtration device 16 is not provided with the water supply unit 28 and only has the discharge unit 26 as an outlet for the permeated water, the third pipe 36 may be connected to the fifth pipe 39 upstream of the connection with the fourth pipe 38, so that a portion of the permeated water in the concentration step is sent to the third pipe 36 and flows into the flow injection system. Alternatively, if the membrane filtration device 16 is not provided with the discharge unit 26 and only has the water supply unit 28 as an outlet for the permeated water, the fifth pipe 39 may be connected via the second valve 62 to the third pipe 36 upstream of the reagent injection unit 44, so that a portion of the permeated water is discharged to the outside of the system through the fifth pipe 39.

[0055] In the analyzer 124, during the concentration step, the fifth valve 68 is opened and the fourth valve 66 is closed. Then, the preconcentration pump 14 supplies the water to be analyzed to the membrane filtration device 16 via the pipe 18. At this time, the flow of the water to be analyzed that has flowed into the membrane filtration device 16 is the same as that of the analyzer 122.

[0056] The concentration step is carried out for a predetermined period of time, and then the analysis step is carried out. During the analysis step, while the water to be analyzed is being supplied to the pipe 18, the fifth valve 68 is closed and the fourth valve 66 is opened. The water to be analyzed supplied to the pipe 18 is then supplied from the pipe 18 through the fourth pipes 38 and 39 to the membrane filtration device 16 via the discharge section 26 in the opposite direction to the flow of the permeate during the concentration step. The flow path for the water to be analyzed formed by the closed fifth valve 68 and the open fourth valve 66 constitutes a backwash mechanism. The water to be analyzed shared from the discharge section 26 to the membrane filtration device 16 passes through the filtration membrane within the membrane filtration device 16, causing the analytes accumulated in the membrane filtration device 16 to flow downstream from the concentrated water outlet 24 of the membrane filtration device 16. As with the analyzer 122 shown in FIG. 4, the first valve 60 is opened and the third valve 64 is closed. Therefore, the analytes pushed out by the water to be analyzed are sent to the flow injection system 40 as sample water via the first pipe 32. In the analysis process, the permeate from the membrane filtration device 16 is sent from the water supply section 28 through the third pipe 36 to the flow injection system 40, and during this process, a reagent is added by the reagent injection section 44. In this way, by increasing the backwash water flow rate, the entire amount of endotoxin on the membrane surface of the ultrafiltration membrane can be flushed to the measurement side, so that fine particles can be flushed out without using hydrogen water or functional water containing a drug. Furthermore, because there is no need to use functional water, it is possible to avoid any effect on the reactivity of endotoxin with the reagent.

[0057] FIG. 6 is a diagram illustrating an analytical apparatus 125 according to another embodiment of the present invention. The analytical apparatus 125 shown in FIG. 6 differs from the analytical apparatus 124 shown in FIG. 5 in that it constantly flows a reagent through the flow injection system 40 throughout the concentration and analysis steps. Therefore, instead of the bypass piping 80 of the analytical apparatus 124 shown in FIG. 5, the analytical apparatus 125 shown in FIG. 6 has a second piping 34 connected to the first piping 32, and a third valve 64 is provided on the second piping 34. As a result, during the concentration step, the third valve 64 is opened to send the permeated water to the flow injection system 40 through the second piping 34. During the analysis step, the third valve 64 is closed to stop the supply of permeated water, allowing only the sample water to be sent to the flow injection system 40. Furthermore, throughout the concentration and analysis steps, the reagent is constantly sent from the reagent injector 44 to the flow injection system 40 through the third piping 36, allowing the reagent and the sample water to be mixed.

[0058] The discharge structure for the permeated water from the membrane filtration device 16 may have only one outlet for the permeated water. For example, if the membrane filtration device 16 is not provided with the water supply unit 28 and only has the discharge unit 26 as an outlet for the permeated water, the second pipe 34 may be connected to the fifth pipe 39 upstream of the connection with the fourth pipe 38, and a portion of the permeated water in the concentration step may be sent to the second pipe 34 and flowed into the flow injection system. Alternatively, if the membrane filtration device 16 is not provided with the discharge unit 26 and only has the water supply unit 28 as an outlet for the permeated water, the fifth pipe 39 may be connected via the second valve 62 to the second pipe 34 upstream of the third valve 64, and a portion of the permeated water may be discharged to the outside of the system through the fifth pipe 39.

[0059] 7 is a graph showing a schematic diagram of the change in concentration of concentrated water measured by the analyzer of this embodiment and a conventional analyzer. The horizontal axis represents time t, and the vertical axis represents the analyte concentration C. The solid line shows the change in concentration of concentrated water measured by the analyzer 12 of this embodiment. The dashed line shows the change in concentration of the analyte in sample water measured by a conventional analyzer (see, for example, Patent Document 3) that analyzes the analyte while concentrating it by continuously performing cross-flow filtration.

[0060] In Fig. 7, t0 is the start time of the concentration step, t1 is the start time of the analysis step (i.e., the end time of the concentration step), and t2 is the end time of the analysis step. In Fig. 7, the arrival time of water from the membrane filtration device 16 to the analyzer 48 is 0 (zero), that is, the water discharged from the membrane filtration device 16 reaches the analyzer 48 immediately after being discharged.

[0061] In the analysis device 12 of this embodiment, the concentration gradually increases from time t1, and p Peak concentration at C p The concentration peak is clearly observed in the analysis step. On the other hand, no concentration peak is observed in the analysis device of the prior art. This indicates that in this embodiment, the analyte concentrated in the membrane filtration device 16 in the concentration step temporarily becomes highly concentrated when supplied to the flow injection system 40 in the analysis step, causing a peak to appear, whereas in the conventional continuous cross-flow filtration method, the change in the concentration of the concentrated water is small.

[0062] In Figure 7, the value obtained by multiplying the area of ​​the figure enclosed by the graph between t1 and t2 and the time axis and concentration axis by the flow rate in the analysis process indicates the number of analytes concentrated in the membrane filtration device 16 in the concentration process. From these facts, the concentration of the analyte in the water to be analyzed can be expressed by the following formula (1).

[0063]

number

[0064] Note that FIG. 7 is a schematic representation of the concentration change, and in actual analysis, the concentration is calculated quantitatively using the fluorescence intensity or the like. Here, if a sufficient number of measurement points cannot be obtained (for example, if only one data point (e.g., a peak value) is obtained), the concentration can be determined by applying one of the following methods, for example. One method is to measure a standard sample of known concentration in advance, create a calibration curve based on the results, and estimate the concentration by comparing the obtained peak value. The other method is to adjust the conditions so that the timing at which endotoxin reaches the flow injection system matches the timing of measurement by the flow injection system, and then measure the peak value directly. In either method, if the supply flow rate changes, the timing at which the peak arrives will fluctuate, making it difficult to accurately estimate the concentration. For this reason, it is preferable to always keep the supply flow rate constant. [Example]

[0065] Next, examples will be described, but the present invention is not limited to the following examples.

[0066] In this embodiment, the endotoxin concentration of the water to be analyzed was analyzed using an analyzer 12 similar to that shown in FIG. 1. Endotoxin (standard endotoxin: MERCK, product number L2880) was added to water for injection to a concentration of 0.1 EU / mL (1 pM) to prepare the water to be analyzed. Generally, the potency of 100 pg of endotoxin corresponds to 1 EU, so 100 EU / mL was converted to 1 nM. In a comparative example, analysis was performed using the analyzer described in Patent Document 3, which concentrates endotoxin using a conventional concentration method that involves continuous cross-flow filtration. The ultrafiltration membrane used in the examples and comparative examples has a molecular weight cutoff of 5 kDa and is made of modified polyethersulfone (MPES).

[0067] In this embodiment and the comparative example, the flow rates are as follows: <Present Embodiment> Permeate flow rate during concentration: 300 mL / min Concentrated water flow rate during analysis: 1 mL / min Comparative Example Concentrate water flow rate: 0.95 mL / min Permeate flow rate (reagent side): 0.95 mL / min Permeate flow rate (drainage side): 300 mL / min <Conditions for implementation> Amount of endotoxin attached to the membrane surface: 8 x 10 -10 (g / cm 2 ) Water flow rate: 300 (mL / min) Analysis water amount: 2 (mL / min) Analysis time: 10(min) Specifications of the ultrafiltration device used in Example 1 and Comparative Example 1: Ultrafiltration device: membrane area 115 cm 2 Ultrafiltration membrane with a nominal pore size of 5 kDa (MIDIKROS manufactured by Repligen, made of modified polyethersulfone (MPES), hollow fiber membrane)

[0068] In this embodiment and the comparative example, the measurement conditions were an excitation wavelength of 350 nm, a detection fluorescence wavelength of 500 nm, a fluorescent reagent Zn-dpa-C2OPy (see chemical formula (1) below), and a fluorescent reagent concentration of 10 μM at the reagent injection port. In the example, the flow rate of the permeate in the concentration step was 300 mL / min, and the flow rate of the concentrated water in the analyzer step was 1 mL / min. [ka]

[0069] The measurement conditions for the Examples and Comparative Examples were an excitation wavelength of 350 nm and a detection fluorescence wavelength of 500 nm.

[0070] The measurement results for the examples and comparative examples are shown in Table 1.

[0071] (Table 1) Measurement results of endotoxin (ET) concentration peaks in Examples and Comparative Examples TIFF0007777841000004.tif22159

[0072] As shown in Table 1, in the example, a concentration peak was detected as shown in Figure 7. On the other hand, in the comparative example, no concentration peak was detected. This shows that in this embodiment, endotoxin is more concentrated than in the comparative example, and that endotoxin can be detected by the flow injection system even in a low concentration range.

[0073] Table 2 below shows the relationship between the estimated endotoxin concentration ratio and flux obtained under the following conditions in Examples a and c and Comparative Example b.

[0074] (Conditions for implementation) Example A An analytical device 12 similar to that shown in FIG. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, material MPES (modified polyethersulfone) Filtration conditions: Dead end filtration, filtration time 15 minutes, UF inlet pressure 0.16 MPa, permeate flow rate 300 mL / min, flux 27 mm / min Flow rate during analysis: concentrated water 0.95 mL / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Comparative example b The analytical device shown in Figure 1 of Patent No. 7606197 was used. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, material MPES (modified polyethersulfone) Filtration conditions: cross-flow filtration, UF inlet pressure 0.16 MPa, Permeate flow rate 300mL / min, flux 27mm / min, Concentrated water flow rate 0.95mL / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Example C ·Flux 91mm / min Other conditions were the same as in Example A.

[0075] (Table 2) Estimated concentration ratios and fluxes * Estimated concentration ratio: This shows the relative ratio of the concentration estimated by each Example or Comparative Example, assuming the actual concentration of endotoxin contained in the water being analyzed is 1.00. The closer the value is to 1, the more accurately it reflects the actual concentration.

[0076] The results of a series of Examples and Comparative Examples based on Table 2 revealed the following findings. First, it was shown that the dead-end filtration method had a better estimated concentration ratio than the conventional cross-flow filtration method. This is thought to be because endotoxin accumulated on the membrane surface is efficiently removed by backwashing or flushing.

[0077] Second, if the flux is too high, the endotoxin cannot be maintained in a highly dispersed state on the membrane surface, which is thought to result in a decrease in the estimated concentration ratio.

[0078] Table 3 shows the relationship between the estimated endotoxin concentration ratios and membrane materials obtained under the following conditions in Examples (A) and (C) and Comparative Example (A). (Conditions) Example (A) An analytical device 12 similar to that shown in FIG. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, membrane material: MPES (modified polyethersulfone) Filtration conditions: Dead end filtration, filtration time 15 minutes, UF inlet pressure 0.16 MPa, permeate flow rate 300 mL / min, flux 27 mm / min Flow rate during analysis: concentrated water 0.95 mL / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Comparative Example (i) The analytical device shown in Figure 1 of Patent No. 7606197 was used. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, membrane material: MPES (modified polyethersulfone) Filtration conditions: cross-flow filtration, UF inlet pressure 0.16 MPa, Permeate flow rate 300mL / min, flux 27mm / min, Concentrated water flow rate 0.95mL / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Example (U) ·UF membrane material changed to CA (cellulose acetate) Other conditions are the same as Example (A)

[0079] (Table 3) Estimated concentration ratio and membrane material TIFF0007777841000006.tif32168

[0080] The results of a series of examples and comparative examples based on Table 3 revealed the following findings. Compared to the cross-flow filtration method, the dead-end filtration method showed a high estimated concentration ratio regardless of the membrane material, confirming good detection efficiency. Even under the same flow rate and flux conditions, differences in the estimated concentration ratio occurred depending on the membrane material used, suggesting that the selection of material is an important factor affecting analytical accuracy. In particular, MPES (modified polyethersulfone) showed the highest estimated concentration ratio and can be said to be suitable for endotoxin detection. CA (cellulose acetate) also showed a sufficient estimated concentration ratio and is considered a membrane material that can provide accuracy acceptable for practical use.

[0081] Table 4 below shows the relationship between the estimated concentration ratio and the amount of attached endotoxin obtained under the following conditions in Examples (k), (k) and Comparative Example (g). (Conditions) Example (a) An analytical device 12 similar to that shown in FIG. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, material MPES (modified polyethersulfone) Filtration conditions: Dead end filtration, filtration time 15 minutes, UF inlet pressure 0.16 MPa, permeate flow rate 300 mL / min, flux 27 mm / min Flow rate during analysis: concentrated water 0.95 mL / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Adhesion amount to membrane: 7×10 -9 g / cm 2 Comparative Example (K) The analytical device shown in Figure 1 of Patent No. 7606197 was used. Analyte: ET standard solution 0.1EU / mL Ultrafiltration membrane: MIDIKROS, molecular weight cutoff 100 kDa, material MPES (modified polyethersulfone) Filtration conditions: cross-flow filtration, UF inlet pressure 0.16 MPa, Permeate flow rate 300mL / min, flux 27mm / min, Concentrated water flow rate 0.95mL / min Carrier water is ultrapure water: Water flow rate 0.95mm / min Carrier water is ultrapure water. Flow rate: 0.95 mL / min Adhesion amount to membrane: 6×10 -12 g / cm 2 Example (K) ·Permeated water flow rate 500mL / min Adhesion amount to membrane: 9 x 10 -5 g / cm 2 Other conditions are the same as in Example (a)

[0082] (Table 4) Estimated concentration ratio and deposition amount TIFF0007777841000007.tif22168

[0083] From the results of a series of Examples and Comparative Examples based on Table 4, the following findings were obtained. In the dead-end filtration method, a tendency was observed for the amount of endotoxin adhering to the membrane surface to be greater than in the cross-flow method. This indicates that endotoxin is more likely to accumulate efficiently on the membrane surface because all of the feed water is filtered. Furthermore, in Example (<), in which the permeate flow rate was increased, the amount of endotoxin adhering to the membrane increased significantly, suggesting that an increase in the feed flow rate affects adhesion behavior. On the other hand, when the amount of endotoxin adhering to the membrane becomes excessive, the proportion of endotoxin guided outside the membrane by flushing in the analysis process decreases, and as a result, the estimated concentration ratio tends to decrease. [Explanation of symbols]

[0084] 12, 12A, 12B, 12C...Analyzer, 14...Preconcentration pump, 16...Membrane filtration device, 18, 32, 34, 36, 38, 39...Piping, 20...Outer cylinder, 22...Inlet section, 24...Outlet section, 26...Discharge section, 28...Water supply section, 30...Ultrafiltration membrane, 31...Discharge pipe, 40...Flow injection system, 42...Pump, 44...Reagent injection section, 46...Confluence pipe, 48...Analyzer, 50...Outlet pipe, 60, 62, 64, 66, 68...Valve, 70...Loop pipe, 80...Bridge pipe

Claims

1. a flow injection system that reacts an analyte with a reagent in water and analyzes the analyte using a reaction product produced; A membrane filtration device equipped with a hollow fiber microfiltration membrane or a hollow fiber ultrafiltration membrane; a concentration mechanism configured to form a flow path for the water to be analyzed so that the water to be analyzed is accumulated in the membrane filtration device; a flushing mechanism configured to form a flow path for the analyte water accumulated in the membrane filtration device so that the analyte water flows into the flow injection system together with the concentrated water of the membrane filtration device; a switching mechanism for switching between the concentration mechanism and the flushing mechanism; a reagent injection unit that supplies the reagent to the flow injection system; An analytical device comprising:

2. The analyzer according to claim 1 , wherein the concentration mechanism performs dead-end filtration using the membrane filtration device.

3. The flushing mechanism causes the entire amount of feed water of the membrane filtration device to flow from the concentrated side to the flow injection system. The analytical device of claim 1 .

4. The flushing mechanism causes 50% or more of the feed water of the membrane filtration device to flow into the flow injection system as concentrated water. The analytical device of claim 1 .

5. The permeate from the membrane filtration device is passed through a reagent line into the flow injection system; the reagent injection unit injects the reagent into the reagent line; The analytical device according to claim 4 .

6. The switching mechanism alternately switches between the concentration mechanism and the flushing mechanism, and is capable of continuously analyzing the analyte. The analytical device of claim 1 .

7. The flushing mechanism includes a backwashing mechanism that supplies water from the permeation side of the membrane filtration device and causes the analyte to flow out from the concentration side of the membrane filtration device. The analytical device of claim 1 .

8. The flow injection system is capable of quantitatively analyzing the analyte. The analytical device according to any one of claims 1 to 7.

9. 1. An analytical method for analyzing an analyte using a reaction product produced by reacting the analyte with a reagent in water, comprising: a concentration step of accumulating the analyte on one or more filtration membranes selected from a hollow fiber microfiltration membrane and a hollow fiber ultrafiltration membrane; an analysis step of flowing the reagent into the flow injection system while flowing the accumulated analyte together with the concentrated water of the filtration membrane into the flow injection system; The analytical method has the following features.

10. The analytical method according to claim 9 , wherein dead-end filtration is performed with the filtration membrane in the concentration step.

11. The analytical method according to claim 9 , wherein the reagent is flowed into the flow injection system together with the permeate of the filtration membrane.

12. The analytical method according to claim 9 , wherein in the analyzing step, the entire amount of water supplied to the filtration membrane is passed through the flow injection system as the concentrated water.

13. The analysis method is capable of quantitatively analyzing the analysis target. The analytical method according to any one of claims 9 to 12.

14. The concentration step and the analysis step can be alternately switched to continuously analyze the analyte. The analytical method according to any one of claims 9 to 12.

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