Online protein concentration detection device capable of expanding concentration range

Abstract

The utility model relates to the field of culture solution concentration detection, in particular to an on-line protein concentration detection device for expanding a concentration range. The device comprises a first injection pump, a selector valve, a container assembly, a dilution and detection assembly and an air filter, the selector valve is provided with a public port and six selection ports uniformly distributed around the public port, and the public port is communicated with one of the six selection ports; a buffer ring is communicated between the first injection pump and the common port of the selection valve; the container assembly comprises a calibration standard liquid container, a first cleaning liquid container, a second cleaning liquid container and a culture container; the dilution and detection assembly comprises a three-way valve, a dilution assembly and a detection assembly respectively communicated with two ends of the three-way valve, and a sample reserving valve communicated with the output end of the detection assembly. According to the utility model, the detection concentration range is expanded to 6.5 orders of magnitude, the requirement of the protein measurement concentration range from extremely low concentration to extremely high concentration in the whole cell culture process is met, and the measurement accuracy and sensitivity are high.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of culture solution concentration detection, especially relate to an online protein concentration detection device of extension concentration range. BACKGROUND

[0002] The general protein concentration detection scheme at present is relying on the ultraviolet light absorption of protein at 280nm, and the protein concentration is calculated by measuring the extinction coefficient. In the linear range of detector, the ultraviolet light absorption of protein solution obeys Beer-Lambert Law: A = lg (1 / T) = epsilon b, wherein A is absorbance, T is transmittance, which is the ratio of emergent light and incident light intensity, c is the concentration of light-absorbing substance, b is the thickness of solution layer shielding light, and epsilon is molar absorption coefficient. For protein, the molar absorption coefficient epsilon of peptide or protein at 280nm is related to the composition of tryptophan (W), tyrosine (Y) and cysteine (C) amino acids, and the value is related to the weighted extinction coefficient of the three amino acids at 280nm:

[0003] Epsilon = (nW * 5500) + (nY * 1490) + (nC * 125).

[0004] In the linear range of ultraviolet spectrophotometric measurement, the protein concentration is proportional to the ultraviolet absorbance A. Therefore, the protein concentration information can be obtained by measuring the ultraviolet absorbance at 280nm. The ultraviolet spectrophotometer is a commonly used measuring device in the field. If continuous measurement is required during a culture period, the culture container is generally connected with a liquid delivery device such as a peristaltic pump which can deliver liquid to the outside, and the culture solution is guided into an open quartz cuvette or a quartz flow cell with sealed interfaces at both ends. During the whole measurement period, the optical path of the flow cell remains constant. If the sample concentration is too large during the process, it is generally necessary for the experimenter to manually change to a small optical path flow cell or dilute the sample.

[0005] The prior art mainly has the following deficiencies:

[0006] 1. When the optical path (the thickness of the protein solution layer flowing through) of the cuvette / flow cell is fixed, the linear range of ultraviolet spectrometric detection is generally only 3.5 orders of magnitude (the effective measurement range of absorbance A is 0.001-2Au), even if a short optical path flow cell is used, when the protein concentration in the sample is high, the measurement result will still exceed the linear range, resulting in an increase in the deviation of the calculated concentration value.

[0007] 2. If a very short optical path flow cell (such as a flow cell with only 0.1mm liquid layer thickness) is used to extend the high concentration limit, the measurement sensitivity is insufficient due to the low signal of low concentration sample. UTILITY MODEL CONTENTS

[0008] The utility model discloses a kind of online protein concentration detection devices of extension concentration range, the detection concentration range is extended to 6.5 orders of magnitude, meet the requirement of protein measurement concentration range from extremely low to extremely high concentration in whole cell culture, measurement precision and sensitivity are high.

[0009] The utility model discloses a kind of online protein concentration detection devices of extension concentration range, including first injection pump, selection valve, container assembly, dilution and detection component and air filter;Selection valve has a public port and six selection ports that are evenly distributed around the public port, the public port is communicated with six selection ports alternatively;Buffer ring is communicated between first injection pump and the public port of selection valve;Container assembly includes respectively with the calibration standard solution container, first washing liquid container, second washing liquid container and culture container of four selection ports of selection valve communication;Dilution and detection component includes tee valve, dilution component and detection component respectively with tee valve two ends communication and with the output end of detection component communication sample valve, detection component includes first ultraviolet photometric detector and second ultraviolet photometric detector, tee valve, first ultraviolet photometric detector, second ultraviolet photometric detector and sample valve are communicated in turn, first ultraviolet photometric detector carries first flow cell with 0.3mm optical path, second ultraviolet photometric detector carries second flow cell with 10mm optical path;Air filter and the remaining one end of tee valve are communicated with the remaining two selection ports of selection valve respectively.

[0010] Preferably, selection valve includes valve body, stator arranged in valve body and rotor rotationally arranged on stator, public port and selection port are located on valve body, the outer end of rotor has slot, and has passage inside, when slot is oriented to any selection port, the selection port is communicated with public port.

[0011] Preferably, buffer ring is a section of inert pipeline with internal volume consistent with the range of first injection pump.

[0012] Preferably, dilution component includes liquid suction valve, second injection pump and dilution liquid container;Liquid suction valve is two-position three-way valve, public end is communicated with second injection pump, normally open end is communicated with dilution liquid container, and normally closed end is communicated with three-way valve.

[0013] Preferably, first injection pump and second injection pump all adopt glass outer cylinder and polytetrafluoroethylene piston.

[0014] Preferably, the specification of second injection pump is greater than that of first injection pump.

[0015] Preferably, sample valve is two-position three-way valve, and liquid suction valve and sample valve both have polytetrafluoroethylene lining.

[0016] Compared with prior art, the utility model has the following beneficial technical effects:

[0017] The utility model discloses two series connection, the light path unequal flow cell, can realize wider range linear coverage. Simultaneously, the pump and valve switching system are added on the device, can carry out the dilution of sample simultaneously in the process of ultraviolet detection, realizes the linear range of more than 6.5 orders of magnitude on the same device, satisfies the requirement of the protein measurement concentration range from very low to very high concentration in the whole cell culture, and the measurement precision and sensitivity are high. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is structural schematic diagram of the utility model embodiment.

[0019] The figure mark: 1, first injection pump;2, buffer ring;3, selection valve;4, calibration standard solution container;51, first cleaning liquid container;52, second cleaning liquid container;6, culture container;7, three-way valve;8, liquid suction valve;9, second injection pump;10, dilution liquid container;11, first ultraviolet photometric detector;12, second ultraviolet photometric detector;13, sample valve;14, air filter. DETAILED DESCRIPTION

[0020] As Figure 1 The utility model discloses a kind of online protein concentration detection devices of extended concentration range, including first injection pump 1, selection valve 3, container assembly, dilution and detection assembly and air filter 14.

[0021] Selection valve 3 has a common port and six selection ports (numbered 1-6) evenly distributed around the common port, and the common port is in communication with the six selection ports. Selection valve 3 is used to select different liquid paths and is suitable for general cell culture container sampling and cleaning. Selection valve 3 includes a valve body, a stator disposed in the valve body, and a rotor rotatably disposed on the stator. The common port and the selection ports are located on the valve body. The outer end of the rotor has a slot and an internal passage. When the slot is directed at any selection port, the selection port is in communication with the common port. The valve body, rotor, and stator are made of an inert material that does not react with the analyte and the reagents used. The material is 316L stainless steel.

[0022] A buffer ring 2 is connected between the first injection pump 1 and the common port of the selection valve 3. The first injection pump 1 and the matching buffer ring 2 are configured according to the required reagent volume. The injector is suitable for general cell culture container sampling specifications, with a delivery volume step of 0.001 mL and a buffer ring 2 volume of 1 mL. The buffer ring 2 is a section of inert pipeline with an internal volume consistent with the range of the first injection pump 1, ensuring that the liquid taken by the first injection pump 1 only enters the buffer ring 2 and does not contaminate the first injection pump 1.

[0023] The container assembly includes a calibration standard solution container 4, a first washing solution container 51, a second washing solution container 52 and a culture solution container 6, which are respectively connected with four selection ports of the selection valve 3. The calibration standard solution container 4 contains calibration solution. The first washing solution container 51 contains washing solution A (sodium hypochlorite solution), the second washing solution container 52 contains washing solution B (pure water), and the culture solution container 6 contains culture solution.

[0024] The dilution and detection assembly includes a three-way valve 7, a dilution assembly and a detection assembly connected with two ends of the three-way valve 7 respectively, and a sample holding valve 13 connected with an output end of the detection assembly. The sample holding valve 13 is used for waste or sample holding, and is a two-position three-way valve with a polytetrafluoroethylene lining. When sample holding is required, the sample holding valve 13 is switched to the sample holding port, and the culture solution sample is injected into an externally connected sample holding container.

[0025] The detection assembly includes a first ultraviolet photometric detector 11 and a second ultraviolet photometric detector 12, and the three-way valve 7, the first ultraviolet photometric detector 11, the second ultraviolet photometric detector 12 and the sample holding valve 13 are connected in sequence. The first ultraviolet photometric detector 11 is equipped with a first flow cell with an optical path of 0.3 mm, and the first flow cell is a short optical path flow cell. The second ultraviolet photometric detector 12 is equipped with a second flow cell with an optical path of 10 mm, and the second flow cell is a long optical path flow cell. The detector is used to measure the real-time ultraviolet absorption of the column effluent, uses an LED as a light source, and is a single-wavelength ultraviolet detector for measuring absorbance at a fixed wavelength of 280 nm. A conventional ultraviolet photometric detector can also be used. After the chromatographic effluent is introduced into the quartz flow cell, the absorption of the effluent to the LED light source is measured using a photocell to measure the concentration of the protein.

[0026] The dilution assembly includes a suction valve 8, a second injection pump 9 and a dilution solution container 10. The suction valve 8 is a two-position three-way valve with a polytetrafluoroethylene lining, a common end connected with the second injection pump 9, a normally open end connected with the dilution solution container 10, and a normally closed end connected with the three-way valve 7. The second injection pump 9 is used to quantitatively suck and push out the dilution solution, and to online dilute the measured cell culture solution pushed out by the first injection pump 1. The suction of the second injection pump 9 is controlled by the suction valve 8. In order to meet the accuracy of common 5-100 times dilution, the specification of the second injection pump 9 is larger than that of the first injection pump 1.

[0027] Both the first injection pump 1 and the second injection pump 9 are air-tight syringes, both of which use a glass outer cylinder and a polytetrafluoroethylene piston.

[0028] An air filter 14 and the remaining one end of the three-way valve 7 are respectively connected with the remaining two selection ports of the selection valve 3. The air filter 14 is used to filter possible microorganisms in the sample. It prevents the introduction of exogenous microbial contamination of the system when using gas purging. The air filter 14 uses a polytetrafluoroethylene membrane air filter with a pore size of 0.22 um.

[0029] For the specific connection of the six selection ports of the selection valve 3: the calibration standard solution container 4 is in communication with port 1, the first cleaning solution container 51 is in communication with port 2, the second cleaning solution container 52 is in communication with port 3, the culture container 6 is in communication with port 4, the three-way valve 7 is in communication with port 5, and the air filter 14 is in communication with port 6.

[0030] Generally, the effective linear range of ultraviolet spectrometry is 0.001 Au-2 Au. In order to expand the linear range of the detector, the measuring mode of the device is as follows:

[0031] The calibration solution in the calibration standard solution container 4 is a standard solution with a known absorbance at 280 nm. It produces an absorbance of about 0.033 Au on the first flow cell with an optical path of 0.3 mm. Correspondingly, it produces an absorbance of 1 Au on the second flow cell with an optical path of 10 mm. The standard sample is within the linear range on both detectors.

[0032] Because of the uncertainty of the machining of the flow cell, the actual optical path ratio of the two cells is calculated from the absorbance ratio of the calibration solution on the two detectors.

[0033] If the absorbance of the calibration solution measured on the first ultraviolet photometric detector 11 is A1, and the response on the first ultraviolet photometric detector 11 is A2, then the optical path ratio of the two detectors is K=A2 / A1. Therefore, for the same sample, the signal measured on the first ultraviolet photometric detector 11 is amplified by K times, and the signal value of the second ultraviolet photometric detector 12 is obtained. At this time, for a test sample, if the signal value read by the second ultraviolet photometric detector 12 is >2 Au, which exceeds its linear range, then the signal is read through the short optical path flow cell and amplified by K times to obtain the actual response of the sample. Because K is about 30 times (the ratio of the optical paths of the two flow cells is about 10 / 0.3=33.3). At this time, considering that the upper limit of the linear range of the first ultraviolet photometric detector 11 is 2 Au, the sample concentration is converted to the response on the second ultraviolet photometric detector 12 as 2*K≈60 Au. That is, through the setting of the double optical path flow cell, the linear range of ultraviolet detection is expanded from 0.001-2 Au to 0.001-60 Au.

[0034] When the signal read by the first ultraviolet photometric detector 11 also exceeds 2 Au, the system will again draw the sample, and the first injection pump 1 and the second injection pump 9 push out at a certain cooperative speed. When the flow rate of the diluent pushed out by the second injection pump 9 is n times that of the first injection pump 1, the sample is diluted to 1 / (n+1) times the original concentration. Define the dilution ratio D=n+1. After the system measures the signal of the short optical path cell, the signal is amplified by the dilution ratio D and the optical path ratio K, and the absorption result equivalent to that of the undiluted sample directly measured using the 10 mm long optical path flow cell can be obtained.

[0035] In actual use, because the dilution ratio is generally not less than 5, the volume ratio of the two injectors is designed to be 1:10, the first injection pump 1 is 1 mL / min, and the second injection pump 9 is 10 mL. The piston advance speed ratio of the two injection pumps is adjusted in the range of 1:0.4-1:9.9, and under different speed ratios, the sample can be accurately diluted by 5-100 times.

[0036] At the maximum dilution ratio, the upper limit of the linear range is 2Au*K*D≈6000Au. That is, the device covers the linear range of the absorbance of the protein in the culture medium from 0.001-6000Au, which is as wide as 6.5 orders of magnitude.

[0037] This embodiment uses an ultraviolet spectrophotometer with flow cells for measurement, but uses two flow cells in series with different optical paths, which can achieve wider linear coverage. At the same time, the pump and valve switching system is added to the device, which can dilute the sample during ultraviolet detection, and realize a linear range of more than 6.5 orders of magnitude on the same device, meet the requirements of measuring the concentration of protein from very low to very high concentration in the whole cell culture process, and has high measurement accuracy and sensitivity. The device can be integrated into a small-sized machine body with a total weight of about 5 kg, and the device has a data interface for online measurement and on-site analysis.

[0038] The detection device can realize the following functions:

[0039] Function 1, automatic correction of the ultraviolet detector;

[0040] Function 2, automatic sampling and absorbance detection of the culture medium sample;

[0041] Function 3, automatic sampling, online dilution and absorbance detection of the culture medium sample;

[0042] Function 4, automatic sampling of the culture medium;

[0043] Function 5, pipeline cleaning.

[0044] The specific implementation modes of the above five functions are as follows:

[0045] Function 1, automatic correction of the ultraviolet detector (the sample valve is defaulted to be waste all the time during the process):

[0046] S1.1, the first injection pump 1 sucks 0.05 mL of air from the port 6 into the buffer ring 2;

[0047] S1.2, the first injection pump 1 sucks 1 mL of cleaning liquid B (pure water) from the port 3 into the buffer ring 2;

[0048] S1.3, the first syringe pump 1 pushes out all 1.05 mL to the first flow cell and the second flow cell through port 5, cleaning the flow cell;

[0049] S1.4, the first syringe pump 1 sucks 0.05 mL of air from port 6 into the buffer loop 2;

[0050] S1.5, the first syringe pump 1 sucks 1 mL of cleaning solution B (pure water) from port 3 into the buffer loop 2;

[0051] S1.6, the first syringe pump 1 pushes out 0.8 mL to the first flow cell and the second flow cell through port 5, and then the two ultraviolet detectors measure the blank;

[0052] S1.7, the first syringe pump 1 pushes out the remaining to the first flow cell and the second flow cell through port 5;

[0053] S1.8, the first syringe pump 1 sucks 1 mL of ultraviolet standard solution with an absorbance of 1 Au / cm from port 1;

[0054] S1.9, the first syringe pump 1 pushes out 0.8 mL of ultraviolet standard solution through port 5, rinses and fills the first flow cell and the second flow cell;

[0055] S1.10, read the signals of the two ultraviolet detectors, the response ratio of the first ultraviolet detector 11 and the second ultraviolet detector 12 is the optical path ratio K;

[0056] S1.11, execute pipeline cleaning (see the steps of function 5).

[0057] Function 2, automatic sampling and absorbance detection of culture solution sample (the sample valve is set to waste all the time during the process):

[0058] S2.1, the first syringe pump 1 sucks 0.05 mL of air from port 6 into the buffer loop 2;

[0059] S2.2, the first syringe pump 1 sucks 1 mL of cleaning solution B (pure water) from port 3 into the buffer loop 2;

[0060] S2.3, the first syringe pump 1 pushes out all 1.05 mL to the first flow cell and the second flow cell through port 5, cleaning the flow cell;

[0061] S2.4, the first syringe pump 1 sucks 0.05 mL of air from port 6 into the buffer loop 2;

[0062] S2.5, the first syringe pump 1 sucks 1 mL of cleaning solution B (pure water) from port 3 into the buffer loop 2;

[0063] S2.6, After the first syringe pump 1 pushes 0.8 mL to the first flow cell and the second flow cell, the two LED detectors measure the blank;

[0064] S2.7, The first syringe pump 1 pushes the rest to the first flow cell;

[0065] S2.8, The first syringe pump 1 sucks 0.05 mL air from port 6 into the buffer loop 2;

[0066] S2.9, The first syringe pump 1 sucks 1 mL culture solution from port 4;

[0067] S2.10, The first syringe pump 1 pushes 0.8 mL culture solution to port 5, rinses and fills the first flow cell and the second flow cell;

[0068] S2.11, Read the signals of the two LED detectors, then push all the rest in the syringe pump to port 5;

[0069] S2.12, If the first UV detector 11 responds A1≤1.5 Au, the absorbance reading A of the device is A=A1;

[0070] S2.13, If the first UV detector 11 responds A1>1.5 Au, but the second UV detector 12 responds A2≤1.5 Au, read the response A2 of the second UV detector 12, and let the absorbance reading A of the device be A=A2*K;

[0071] S2.14, If the second UV detector 12 responds A2>1.5 Au, let the absorbance reading A of the device be A=A2*K, but mark as overload;

[0072] S2.15, Perform line cleaning (see steps of function 5).

[0073] Function 3, automatic sampling, online dilution and absorbance detection of culture solution sample (sample valve defaults to waste all the way during the process), take dilution by 10 times as an example:

[0074] S3.1, Determine the dilution coefficient D according to the expected value of the concentration during the culture process, or according to the response of the overloaded second UV detector 12, take D=10 as an example.

[0075] S3.2, The first syringe pump 1 sucks 0.05 mL air from port 6 into the buffer loop 2;

[0076] S3.3, The first syringe pump 1 sucks 1 mL cleaning solution B (pure water) from port 3 into the buffer loop 2;

[0077] S3.4, The first syringe pump 1 pushes all 1.05 mL to port 5 to the first flow cell and the second flow cell, and cleans the flow cell;

[0078] S3.5, the first syringe pump 1 draws 0.05 mL air from port 6 into the buffer loop 2;

[0079] S3.6, the first syringe pump 1 draws 1 mL of wash B (pure water) from port 3 into the buffer loop 2, while the syringe pump B draws 5 mL of diluent from reservoir 5;

[0080] S3.7, the first syringe pump 1 pushes 0.8 mL at 0.5 mL / min into port 5, while the second syringe pump 9 pushes at 4.5 mL / min into the tee. At this point the ratio of the flow rates of the liquids is the same as the ratio of the volumes of the diluents. When the flow rate of the diluent pushed by the second syringe pump 9 is 9 times that of the first syringe pump 1, the sample is diluted to 1 / (9+1) = 0.1 times its original concentration, so D = 10. The mixed water-diluent passes through the first flow cell and the second flow cell, and both LED detectors measure the absorbance;

[0081] S3.8, the first syringe pump 1 and the second syringe pump 9 push all the remaining contents into the first flow cell;

[0082] S3.9, the first syringe pump 1 draws 0.05 mL air from port 6 into the buffer loop 2;

[0083] S3.10, the first syringe pump 1 draws 1 mL of culture from port 4, while the second syringe pump 9 draws 5 mL of diluent from reservoir 10;

[0084] S3.11, the first syringe pump 1 pushes 0.8 mL at 0.5 mL / min into port 5, while the second syringe pump 9 pushes at 4.5 mL / min into the tee. At this point the ratio of the flow rates of the liquids is the same as the ratio of the volumes of the diluents. When the flow rate of the diluent pushed by the second syringe pump 9 is 9 times that of the first syringe pump 1, the sample is diluted to 1 / (9+1) = 0.1 times its original concentration, so D = 10. The mixed water-diluent passes through the first flow cell and the second flow cell, and both LED detectors measure the absorbance A1 and A2;

[0085] S3.12, the signals from both LED detectors are read, and then all the remaining contents in the syringes are pushed into port 5;

[0086] S3.13, if the first UV absorbance detector 11 responds with A1 < 1.5 Au, then the absorbance reading A of the device is A = A1 * D;

[0087] S3.14, if the first UV absorbance detector 11 responds with A1 > 1.5 Au, but the second UV absorbance detector 12 responds with A2 < 1.5 Au, then the absorbance reading A of the device is A = A2 * K * D, where K is the ratio of the absorbance of the diluent to the absorbance of the culture;

[0088] S3.15, If the second UV detector 12 responds A2 > 1.5Au, then the system uses the next larger dilution factor for sampling measurement;

[0089] S3.16, Perform line cleaning (see steps of function 5).

[0090] Function 4, Automatic sample saving of culture solution:

[0091] S4.1, The first syringe pump 1 draws 0.5 mL air from port 6 into the buffer loop 2;

[0092] S4.2, The first syringe pump 1 draws 0.5 mL culture solution from port 4 into the buffer loop 2;

[0093] S4.3, Open the sample valve 13, the first syringe pump 1 pushes out 0.5 mL, through the first flow cell and the second flow cell into the sample container;

[0094] S4.4, If a larger sample volume is required, repeat S4.2 and S4.3 until the sample volume meets the requirements;

[0095] S4.5, Close the sample valve 13, and direct the liquid into the waste;

[0096] S4.6, Perform line cleaning (see steps of function 5).

[0097] Function 5, Line cleaning (the sample valve is always in waste by default during the process):

[0098] S5.1, The first syringe pump 1 draws 0.5 mL air from port 6 into the buffer loop 2;

[0099] S5.2, The first syringe pump 1 draws 0.5 mL cleaning solution A (sodium hypochlorite solution) from port 2 into the buffer loop 2;

[0100] S5.3, The first syringe pump 1 pushes out 0.5 mL to port 5, through the first flow cell and the second flow cell, finally into the waste;

[0101] S5.4, Repeat S5.2 and S5.3 multiple times, until the disinfection requirements are met, then push all the remaining volume to port 5;

[0102] S5.5, The first syringe pump 1 draws 0.5 mL air from port 6 into the buffer loop 2;

[0103] S5.6, The first syringe pump 1 draws 0.5 mL cleaning solution B (pure water) from port 3 into the buffer loop 2;

[0104] S5.7, The first syringe pump 1 pushes out 0.5 mL to port 5, through the first flow cell and the second flow cell, finally into the waste;

[0105] S5.8, repeat S5.2 and S5.3 multiple times until the requirement of removing sodium hypochlorite residue is met, then push all the remaining volume to port 5 out;

[0106] S5.9, the first syringe pump 1 sucks 1 mL of air from port 6 into the buffer ring 2;

[0107] S5.10, the first syringe pump 1 pushes 1 mL of air to port 5 out;

[0108] S5.11, repeat S5.9 and S5.10 multiple times until the line and flow cell are drained.

[0109] The embodiments of the utility model are explained in detail above in combination with the drawings, but the utility model is not limited to this, various changes can be made within the knowledge range possessed by the technical personnel in the technical field without departing from the purpose of the utility model.

Claims

1. An online protein concentration detection device with an extended concentration range, characterized in that, include: Selector valve (3) has a common port and six selector ports evenly distributed around the common port, and the common port is connected to one of the six selector ports. A first injection pump (1) is connected to a common port of the selector valve (3) via a buffer ring (2); The container assembly includes a calibration standard solution container (4), a first cleaning solution container (51), a second cleaning solution container (52), and a culture container (6) respectively connected to four selection ports of the selection valve (3); The dilution and detection assembly includes a three-way valve (7), a dilution assembly and a detection assembly connected to both ends of the three-way valve (7) respectively, and a sample retention valve (13) connected to the output end of the detection assembly. The detection assembly includes a first ultraviolet photometric detector (11) and a second ultraviolet photometric detector (12). The three-way valve (7), the first ultraviolet photometric detector (11), the second ultraviolet photometric detector (12) and the sample retention valve (13) are connected in sequence. The first ultraviolet photometric detector (11) is equipped with a first flow cell with an optical path of 0.3 mm, and the second ultraviolet photometric detector (12) is equipped with a second flow cell with an optical path of 10 mm. The air filter (14) and the remaining end of the three-way valve (7) are respectively connected to the remaining two selection ports of the selector valve (3).

2. The online protein concentration detection device with an extended concentration range according to claim 1, characterized in that, The selector valve (3) includes a valve body, a stator disposed in the valve body, and a rotor rotatably disposed on the stator. Both the common port and the selector port are located on the valve body. The outer end of the rotor has a slot and the inside has a passage. When the slot faces any selector port, the selector port is connected to the common port.

3. The online protein concentration detection device with an extended concentration range according to claim 1, characterized in that, The buffer ring (2) is an inert pipeline with an internal volume that matches the range of the first injection pump (1).

4. The online protein concentration detection device with an extended concentration range according to claim 1, characterized in that, The dilution assembly includes a suction valve (8), a second injection pump (9), and a diluent container (10). The suction valve (8) is a two-position three-way valve, with its common end connected to the second injection pump (9), its normally open end connected to the diluent container (10), and its normally closed end connected to the three-way valve (7).

5. The online protein concentration detection device with an extended concentration range according to claim 4, characterized in that, Both the first injection pump (1) and the second injection pump (9) use glass outer cylinders and polytetrafluoroethylene pistons.

6. The online protein concentration detection device with an extended concentration range according to claim 4, characterized in that, The second injection pump (9) has a larger specification than the first injection pump (1).

7. The online protein concentration detection device with an extended concentration range according to claim 4, characterized in that, The sample retention valve (13) is a two-position three-way valve, and both the liquid suction valve (8) and the sample retention valve (13) have polytetrafluoroethylene liners.

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