CN110702896A - Time-resolved fluorescence immunochromatographic assay quantitative detection method for quinolone drugs in yak meat - Google Patents

Abstract

The invention discloses a time-resolved fluorescence immunochromatographic assay quantitative detection method for quinolone drugs in yak meat. The invention provides a detection reagent card, which comprises a bottom plate, a sample pad, a release pad, a nitrocellulose membrane and a water absorption pad, wherein the sample pad is arranged on the bottom plate, the release pad contains an anti-quinolone drug antibody marked by europium microspheres, the nitrocellulose membrane contains a quinolone drug detection line T and a quality control line C, and the water absorption pad is arranged on the nitrocellulose membrane. In the reagent card, the anti-quinolone drug antibody is an anti-ciprofloxacin monoclonal antibody; the amino acid sequence of the light chain variable region of the ciprofloxacin-resisting monoclonal antibody is 1; the amino acid sequence of the heavy chain variable region of the ciprofloxacin-resisting monoclonal antibody is 2. The method is used for detecting the residual quantity of ciprofloxacin in the yak meat by establishing a time-resolved fluorescence immunochromatography method, and the sensitivity of the method is higher than that of an ELISA method.

Description

Time-resolved fluorescence immunochromatographic assay quantitative detection method for quinolone drugs in yak meat

Technical Field

The invention belongs to the technical field of biology, and particularly relates to a time-resolved fluorescence immunochromatography quantitative detection method for quinolone drugs in yak meat.

Background

The yak is one of the special livestock varieties in Qinghai-Tibet plateau. Most of the plants are distributed in alpine grassland pastoral areas, which not only are the foundations and signs of economic development of the Tibetan nationality of alpine grassland and the residential areas of other minority nationalities, but also become independent plates for development of animal husbandry in the Tibetan plateau areas. With the expansion of the yak breeding scale, as farmers basically give priority to herdsmen, the knowledge level is low, the ecological breeding concept is poor, in order to control the occurrence of yak epidemic diseases, the safety of yak meat is seriously influenced by indiscriminate use, abuse and long-term or excessive use of veterinary drugs by the breeders in the breeding process.

Quinolones (QNS for short) are artificially synthesized broad-spectrum antibiotics, and the drugs have the characteristics of high efficiency, low toxicity and broad spectrum, so the Quinolones are widely applied to disease control in livestock husbandry, aquatic product and other breeding industries. The long-term use of quinolones leads to the development of drug residues and resistance, which can be harmful to human health through animal-derived foods. Therefore, quinolone drugs have been listed as important monitoring items for residue detection in animal-derived foods in the european union, the united states and japan, the FDA in the united states announced that the sale and use of enrofloxacin, an antibacterial drug for treating bacterial infection of poultry, was prohibited in 2005, and the highest residue limit of 7 quinolone drugs, ciprofloxacin, mononofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine, in animal muscle tissues was regulated by the 235 th bulletin of animal food by the ministry of agriculture in China to be 10 to 500 μ g/kg.

At present, the detection methods of the quinolone drugs mainly comprise High Performance Liquid Chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), colloidal gold immunochromatography, enzyme-linked immunosorbent assay (ELISA) and the like. Chromatographic methods generally require expensive instruments, are costly to detect, and are complex to operate and unsuitable for basic level detection. The colloidal gold immunochromatography can be used for basic layer detection but cannot perform quantification, the enzyme-linked immunosorbent assay can perform quantitative detection but requires too long reaction time, and the enzyme is unstable.

The Time-resolved fluoroimmunoassay (TRFIA) is a non-isotopic immunoassay developed in recent years, and the Time-resolved fluoroimmunoassay is simple and convenient to operate and easy to realize automation, can effectively eliminate interference of non-specific fluorescence, and greatly improves the analysis sensitivity. The technology has the advantages of both colloidal gold and ELISA, overcomes the defect of unstable enzyme in the ELISA method, and is widely applied to detection of drug residues. At present, no report of applying a time-resolved immunochromatography technology to detect quinolone drugs in yak meat exists.

Disclosure of Invention

In order to detect the carbostyril drug residue in the yak meat, the invention provides the following technical scheme:

the invention aims to provide a quinolone drug time-resolved fluorescence immunoassay reagent card.

The detection reagent card provided by the invention comprises a bottom plate, a sample pad arranged on the bottom plate, a release pad containing an europium microsphere labeled anti-quinolone drug antibody, a nitrocellulose membrane containing a quinolone drug detection line T and a quality control line C, and a water absorption pad.

In the reagent card, the anti-quinolone drug antibody is an anti-ciprofloxacin monoclonal antibody;

the amino acid sequence of the heavy chain variable region of the ciprofloxacin-resisting monoclonal antibody is 1;

the amino acid sequence of the light chain variable region of the ciprofloxacin-resisting monoclonal antibody is 2.

In the reagent card, the europium microsphere-labeled anti-quinolone drug antibody-containing release pad is formed by spraying an europium microsphere-labeled anti-ciprofloxacin antibody solution on the release pad;

the coating concentration of the europium microsphere-labeled anti-ciprofloxacin antibody solution is 1.4 mg/mL.

In the reagent card, in the europium microsphere-labeled anti-ciprofloxacin antibody solution, the mass ratio of the anti-ciprofloxacin antibody to the europium microsphere is 7: 20;

or the europium microspheres are 200nm carboxylated europium microspheres.

In the reagent card, the quinolone drug detection line T is formed by ciprofloxacin antigen or a solution thereof;

or the coating concentration of the ciprofloxacin antigen solution is specifically 1.0 mg/mL;

or, the quality control line C is formed from an IgG antibody or an IgG antibody solution;

or the coating concentration of the IgG antibody solution is specifically 0.875 mg/mL;

or, the cellulose nitrate membrane containing the quinolone drug detection line T and the quality control line C is a cellulose nitrate membrane coated with the ciprofloxacin antigen solution to form a detection line T, and coated with the IgG antibody solution to form a quality control line C, so that the cellulose nitrate membrane containing the ciprofloxacin detection line T and the quality control line C is obtained.

It is another object of the present invention to provide a method for preparing the first object reagent card.

The method provided by the invention comprises the following steps: firstly, preparing a release pad containing an europium microsphere-labeled anti-quinolone drug antibody and preparing a nitrocellulose membrane containing a quinolone drug detection line T and a quality control line C; assembling a sample pad, the release pad containing the europium microsphere-labeled anti-quinolone drug antibody, the nitrocellulose membrane containing the quinolone drug detection line T and the quality control line C and the water absorption pad on a bottom plate to obtain a reagent card;

the release pad containing the europium microsphere labeled anti-quinolone drug antibody is formed by spraying an europium microsphere labeled anti-ciprofloxacin antibody solution on the release pad;

the concentration of the europium microsphere-labeled anti-ciprofloxacin antibody solution is 1.4 mg/mL;

the anti-quinolone drug antibody is an anti-ciprofloxacin monoclonal antibody;

the amino acid sequence of the light chain variable region of the ciprofloxacin-resisting monoclonal antibody is 1;

the amino acid sequence of the heavy chain variable region of the ciprofloxacin-resisting monoclonal antibody is 2;

the quinolone drug detection line T is formed by ciprofloxacin antigen or a solution thereof;

or the coating concentration of the ciprofloxacin antigen solution is specifically 1.0 mg/mL;

the quality control line C is formed by IgG antibody or IgG antibody solution;

or the concentration of the IgG antibody solution is specifically 0.875 mg/mL;

the cellulose nitrate membrane containing the quinolone drug detection line T and the quality control line C is formed by coating ciprofloxacin antigen solution on the cellulose nitrate membrane to form the detection line T, and coating IgG antibody solution on the cellulose nitrate membrane to form the quality control line C, so that the cellulose nitrate membrane containing the quinolone drug detection line T and the quality control line C is obtained.

The application of the reagent card in the first purpose in the preparation of quinolone drug products for detection or auxiliary detection is also within the protection scope of the invention;

or the application of the reagent card in the first purpose in the preparation of a quinolone drug product or in auxiliary detection of the quinolone drug product in a sample to be detected is also within the protection scope of the present invention;

or the application of the reagent card in the first purpose in the preparation of a product for detecting or assisting in detecting the content of the quinolone drugs in a sample to be detected is also within the protection scope of the invention;

or the application of the reagent card in the first object in detection or auxiliary detection of quinolone drugs is also within the protection scope of the invention;

or the application of the reagent card in the first purpose in detecting or assisting in detecting whether the sample to be detected contains the quinolone drugs is also within the protection scope of the invention;

or the application of the reagent card in the first purpose in detecting or assisting in detecting the content of the quinolone drugs in a sample to be detected is also within the protection scope of the invention;

or the application of the europium microsphere-labeled anti-ciprofloxacin antibody in the reagent card in the first purpose in detecting or assisting in detecting whether the sample to be detected contains the quinolone drugs or the content of the quinolone drugs in the sample to be detected is also within the protection scope of the invention.

It is a further object of the present invention to provide a method of:

the invention provides a method for detecting or assisting in detecting whether a sample to be detected contains quinolone drugs, which comprises the following steps: extracting a sample to be detected by using an organic solvent, and collecting an extracting solution; adding the extracting solution to a sample pad of the reagent card for reaction, and detecting a reaction product by using a fluorescence immunoassay quantitative analyzer;

the organic solvent comprises acetonitrile and n-hexane;

if the fluorescence signal value of the detection line T of the reagent card is less than or equal to the fluorescence signal value of the quality control line C, the to-be-detected sample contains or is candidate to contain quinolone drugs;

and if the fluorescence signal value of the detection line T of the reagent card is greater than the fluorescence signal value of the quality control line C, the sample to be detected does not contain or candidate does not contain quinolone drugs.

Or, the invention provides a method for detecting or assisting in detecting the content of the quinolone drugs in a sample to be detected, which comprises the following steps:

1) preparing a standard curve;

taking a sample which has the same source as a sample to be detected and does not contain the quinolone drugs (namely the sample with the content of the quinolone drugs less than 0.1 mu g/kg), adding the quinolone drugs with different concentrations, extracting the sample by using an organic solvent, and collecting extract containing the quinolone drugs with different concentrations; the organic solvent comprises acetonitrile and n-hexane;

adding the extracting solutions with different quinolone drug concentrations to the sample pad of the reagent card for reaction, and testing by using a fluorescence immunoassay quantitative analyzer to obtain a detection line T fluorescence signal value and a quality control line C fluorescence signal value of the reagent card under the condition of standard substance solutions with different concentrations;

taking different concentrations of added quinolone drugs as an X axis, taking the ratio of the fluorescence signal value of the corresponding detection line T to the fluorescence signal value of the quality control line C as a Y axis, and drawing a standard curve;

2) extracting a sample to be detected by using an organic solvent, and collecting a sample extracting solution to be detected; the organic solvent comprises acetonitrile and n-hexane;

adding the sample extracting solution to be detected on a sample pad of the reagent card, reacting for 5min at 40 ℃, and detecting a reaction product by using a fluorescence immunoassay quantitative analyzer to obtain a detection line T fluorescence signal value and a quality control line C fluorescence signal value of the sample to be detected;

substituting the fluorescence signal value of the detection line T and the fluorescence signal value of the quality control line C of the sample to be detected into the standard curve obtained in the step 1) to obtain the content of the quinolone drugs in the sample to be detected.

In the above method, the organic solvent extraction sample comprises the following steps: taking 3 +/-0.05 g of edible muscle tissue of a homogenized yak meat sample, sequentially adding 50 mu L of sample extracting agent (0.1mol/L sulfuric acid aqueous solution), 0.7g of sample purifying agent (neutral aluminum oxide)) and 6mL of acetonitrile, and immediately and fully whirling for 5 min; then centrifuging for 5min by a centrifuge (4000 g); taking 3mL of supernatant fluid into a new 4mL centrifuge tube; drying in 50 deg.C water bath with nitrogen; then adding 2mL of n-hexane, fully whirling for 30s, finally adding 1mL of sample diluent (pH7.4 PBS), and whirling at a low speed for 30 s; centrifuging for 5min at a speed of more than 4000 g; completely removing the upper n-hexane layer and the intermediate layer impurities; taking 100 mu L of the solution to be detected.

In the above, the sample to be tested is a food animal tissue sample; yak edible muscle tissue;

or, the food animal tissue sample is livestock meat, and in the embodiment of the invention, the livestock meat is specifically yak edible muscle tissue.

Or the quinolone medicine is ciprofloxacin, oxolinic acid, danofloxacin, norfloxacin, flumequine, enoxacin, enrofloxacin or ofloxacin.

The invention aims to establish a simple, rapid and high-sensitivity fluorescence quantitative immunochromatography detection method for quinolones drug residues in yak meat by using europium microspheres as an antibody marker, and evaluates the indexes of sensitivity, accuracy, precision and the like so as to provide a rapid detection method for ciprofloxacin residual quantity in yak meat.

The invention detects the residual quantity of the quinolone drugs in the yak meat by establishing a time-resolved fluorescence immunochromatography method, and the sensitivity of the method is far greater than that of an ELISA method. The quantitative detection limit of the invention to the quinolone drugs in the yak meat is 0.5 mug/kg, the addition recovery rate is 70.26-106.73%, and the variation coefficient is 6.51-9.79%; in the actual detection sample, the detection results of the TRFIA and the LC-MS/MS method accord with each other. The method established by the invention has higher accuracy, precision and sensitivity, and can be used for detecting quinolone drugs in yak meat.

Drawings

FIG. 1 is a schematic diagram of a time-resolved fluorescence immunoassay rapid detection reagent card.

FIG. 2 is a standard curve for TRFIA detection of ciprofloxacin.

FIG. 3 shows the time-resolved fluorescence immunochromatography and LC-MS/MS detection results of ciprofloxacin.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Some of the materials in the following examples are as follows:

micropipettor (Eppendorf, Germany), a celestial balance (Tianjin Demant sensor technology Co., Ltd.), a refrigerated centrifuge (Thermo Fisher Scientific, Germany), an ultrasonic cleaning instrument KQ-100E (ultrasonic instruments Co., Ltd., Kunshan), a liquid chromatography-tandem mass spectrometer (Thermo Fisher Scientific, USA), and a sample grinder (Jiuyang JYL-C090); the detection card incubator (WH-400) and the time-resolved fluoroimmunoassay quantitative analyzer (FQ-S2, 365/610nm) were developed by Vidervican Biotechnology Ltd.

Methanol, acetonitrile, dipotassium hydrogen phosphate, hydrochloric acid, sodium hydroxide, tween20, ethyl acetate, n-hexane and the like are purchased from national drug group chemical reagent limited; bovine Serum Albumin (BSA) was purchased from Amresco, usa; 200nm carboxylated europium microspheres (365/610nm, lambda)_ex/λ_em) Purchased from Creative Diagnostics, USA; nitrocellulose membranes (NC membranes) were purchased from Millipore, usa; the sample pad, the absorbent pad, and the PVC base plate were all purchased from shanghai liang xin science and technology limited.

Ciprofloxacin standards were purchased from Sigma, usa, and ciprofloxacin standard solutions were prepared: accurately weighing 1.0mg ciprofloxacin standard, dissolving with methanol, diluting to 10mL to obtain 100ppm ciprofloxacin standard solution, and storing at-20 deg.C.

The goat anti-mouse secondary antibody is obtained by Beijing Weideweikang biotechnology limited.

Preparing a re-dissolving solution: (1)0.1M Tris-HCl, 0.5% BSA, 0.5% Tween20, 5% sucrose, 0.9% NaCl plus 0.02% Proclin 300 was mixed to adjust the pH to 8.0.

Yak meat samples were purchased from a farm market in the Qinghai.

Example 1 preparation of ciprofloxacin hapten, Artificial antigen and monoclonal antibody

Ciprofloxacin antigen

1. Preparation of ciprofloxacin hapten

Adding 15mL of thionyl chloride into a50 mL round-bottom flask, adding 900mg of ciprofloxacin raw material in batches under magnetic stirring at 20 ℃, and performing magnetic stirring at 50 ℃ for 3 hours, and then performing pressure concentration at 60 ℃ to obtain a ciprofloxacin intermediate; adding 650mg of 4-aminobutyric acid, 30mL mg of THF and 836mg of triethylamine into a50 mL round-bottom flask, magnetically stirring at 20 ℃ for 15min, then dropwise adding 10mL of ciprofloxacin intermediate, magnetically stirring at 20 ℃ for 3 h, then concentrating at 35 ℃ under reduced pressure, adding 30mL of water into residue, adjusting pH to 7-7.5 with 1M hydrochloric acid, separating out off white-like solid, filtering, washing a filter cake with 10mL of water, collecting the filter cake, and drying the filter cake by blowing at 50 ℃ for 5 h to obtain 920mg of ciprofloxacin hapten.

2. Preparation of ciprofloxacin antigens

The preparation method of the ciprofloxacin antigen comprises the following specific operation steps:

① dissolving 12.5mg of ciprofloxacin hapten prepared in the step 1 in 2mL of DMF, adding 11mg of 1- (3-dimethylaminopropyl) -3-Ethylcarbodiimide (EDC) and 10mg of N-hydroxysuccinimide (NHS), and stirring at room temperature for reaction for 2 h;

② BSA50mg was weighed and dissolved in 5mL 0.1M sodium bicarbonate buffer;

③ adding ① prepared ciprofloxacin hapten reaction solution into ② prepared BSA solution drop by drop, and stirring at room temperature for reaction overnight;

④ dialyzing ③ reaction solution with PBS at 4 deg.C for 72h, and changing the dialyzate for 6 times to obtain dialyzate;

⑤ filtering the dialysate with 0.22 μm filter membrane under aseptic condition, and storing at-20 deg.C to obtain ciprofloxacin antigen.

Preparation of ciprofloxacin monoclonal antibody

① the ciprofloxacin antigen (ciprofloxacin-BSA) prepared in the step one 2 is taken, 100 mu g of the ciprofloxacin antigen is dissolved in normal saline, the immunogen and Freund's complete adjuvant are mixed in equal volume, the Balb/c female mouse with the age of 6-8 weeks is injected subcutaneously on the back of the neck, the immunogen and the Freund's incomplete adjuvant are mixed in equal volume on the 7 th, 14 th and 28 th days after the initial immunization, the additional immunization is carried out once, the immune complex is 100 mu g/mouse in 3 days before the fusion, and the additional immunization is carried out once without adding the Freund's adjuvant.

② is prepared by conventional methodMixing splenocytes of immunized mice with myeloma cells of mice in logarithmic growth phase (SP2/0), slowly adding preheated fusion agent (PEG4000) within 45s for fusion, suspending with HAT medium, adding appropriate amount of feeder cells, culturing in 96-well culture plate at 37 deg.C and 5% CO₂Culturing in an incubator, half-changing the culture medium with HT after 5 days, and completely changing the culture medium after 9 days.

③ after cell fusion, when the cell grows to 1/4 of the culture hole area, screening hybridoma by step screening method, primarily selecting by indirect ELISA method, coating chemiluminescence micropore plate with coating antigen (the optimal coating concentration and positive serum dilution are titrated by square matrix method in advance), adding culture supernatant of the tested hole, incubating, cleaning, adding goat anti-mouse IgG-HRP and IgM-HRP, OPD for color reaction, screening the positive hole by indirect competition ELISA method, mixing cell supernatant with 100 mug/mL ciprofloxacin in equal volume, acting in 37 deg.C water bath for 30min, adding into coated chemiluminescence micropore plate, using PBS to replace ciprofloxacin as control, the other steps are the same as above, if OD blocked by ciprofloxacin₄₅₀And (3) judging the wells to be positive when the nm value is reduced to below 50% of the control wells, and subcloning the wells which are positive after 2-3 detections by using a limiting dilution method immediately.

④ performing amplification culture of hybridoma after 2-3 times of subcloning and strain establishment, collecting supernatant, measuring titer by indirect ELISA, freezing, injecting 0.5 mL/mouse of liquid paraffin into abdominal cavity of Balb/c mouse of 8-10 weeks old, injecting hybridoma 1-2 × 10 into abdominal cavity after 7-10 days⁶Extracting ascites from the mouse 7-10 days later, and purifying to obtain the ciprofloxacin monoclonal antibody.

And as a result of sequencing, the amino acid sequence of the heavy chain variable region of the ciprofloxacin monoclonal antibody is shown as a sequence 1 in the sequence table, and the amino acid sequence of the light chain variable region of the ciprofloxacin monoclonal antibody is shown as a sequence 2 in the sequence table.

Third, monoclonal antibody specificity analysis

Structural analogs of the target (shown in Table 1) were selected as inhibitors, and IC-ELISA was used to determine the IC of each inhibitor₅₀Cyclopropyl prepared by the twoIC of monoclonal antibody against flexacin₅₀And IC for each inhibitor₅₀The percentage of the ratio was the rate of cross-reaction (CR%), CR (%) (IC of the target compound)₅₀IC of/analogue₅₀)×100。

The results are shown in table 1, and the results show that the ciprofloxacin monoclonal antibody can be used for detecting quinolone drugs including oxolinic acid, danofloxacin, norfloxacin, flumequine, enoxacin, enrofloxacin and ofloxacin.

Table 1 shows the cross-reactivity test of ciprofloxacin antibody and other ciprofloxacin drugs

Example 2 preparation of quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card and establishment of detection method

Preparation of quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card

1. Antibody labeling of carboxylated europium microspheres

The method is optimized on the basis of a 200nm carboxylation time resolution and antibody marking method, and the specific marking method comprises the following steps:

① 50 μ L carboxylated europium microspheres (200nm carboxylated europium microspheres (365/610nm, λ)_ex/λ_em) 1% concentration, kg/L by mass) was added 450. mu.L of an activation buffer (0.05mol/L MES, pH 5.0), sonicated for 5min, ② was added to ① treated solution in order to make the final concentration 1mM each, shaken at room temperature for 30min, centrifuged at 15000g for 10min, and the supernatant was discarded, ③ was obtained by redissolving ② in 500. mu.L of a coupling buffer (0.04mol/L PB, pH 8.0), sonicated for 5min, added 20. mu.L of a 3.5mg/mL ciprofloxacin monoclonal antibody (mass ratio of monoclonal antibody to microsphere 7:20), shaken horizontally at room temperature for 2h, centrifuged at 15000g for 5min, ④ was obtained by ③ in 500. mu.L of a blocking buffer (0.01mol/L PB, 2% BSA, pH 8.0), shaken at 4 ℃ for 4 min), ⑤ was obtained by centrifugation ④ in 15000g for 5min, and the supernatant was again centrifuged at 50. mu.L overnightAnd (3) re-dissolving the microspheres in the solution, performing ultrasonic treatment for 3min by using an ultrasonic instrument, and storing the microspheres at 4 ℃ in a dark place for later use to obtain the carboxylated europium microsphere labeled ciprofloxacin monoclonal antibody (the concentration is 1.4 mg/mL).

2. Assembly of quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card

The ciprofloxacin antigen (6mg/m L, 1:6 dilution) and goat anti-mouse IgG (17.5mg/mL, 1:20 dilution) obtained in example 1 were coated on an NC membrane by a striping machine to serve as a detection line (T line, 0.9. mu.L/cm, coating concentration of ciprofloxacin antigen being 1.0mg/mL) and a quality control line (C line, 0.9. mu.L/cm, coating concentration of goat anti-mouse IgG being 0.875mg/mL), respectively, and the membrane was dried in an oven at 37 ℃ overnight to obtain a nitrocellulose membrane containing the ciprofloxacin detection line T and the quality control line C.

The carboxylated europium microsphere-labeled ciprofloxacin monoclonal antibody prepared in the above step 1 was sprayed onto a release liner (Shanghai gold Biotech Co., Ltd., SB08, 300 x 200mm) at a spray rate of 2.8. mu.L/cm, and the release liner containing the europium microsphere-labeled anti-ciprofloxacin antibody was dried in an oven at 37 ℃ for 2 hours.

Then, a sample pad, a release pad containing an europium microsphere labeled anti-ciprofloxacin antibody, a nitrocellulose membrane containing a ciprofloxacin detection line T and a quality control line C, and a water absorption pad (Shanghai gold-labeled Biotech Co., Ltd., CH37, 300 x 46mm) are sequentially adhered to a PVC base plate, wherein the end head of one end of the base plate is the water absorption pad, the end head of the other end of the base plate is the sample pad, two ends of the nitrocellulose membrane are respectively overlapped and connected with the water absorption pad and the release pad of the europium microsphere labeled anti-ciprofloxacin antibody, the sample pad is pressed on the release pad of the europium microsphere labeled anti-ciprofloxacin antibody, and the test strip is cut into test strips with the width of 3.90mm by a cutting machine, so that the quinolone drug time-resolved fluorescence immunoassay.

Establishment of time-resolved fluoroimmunoassay rapid detection reagent card detection method for quinolone drugs

1. Establishment of quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card qualitative detection method (TRFIA)

1) Sample extraction

Homogenizing yak meat, weighing 3 + -0.05 g of homogenized sample, placing in a50 mL centrifuge tube, sequentially adding 50 μ L of sample extractant (0.1mol/L sulfuric acid aqueous solution), 0.7g of neutral aluminum oxide and 6mL of acetonitrile, immediately and fully vortexing for 5 min; then centrifuging for 5min by a centrifuge (4000 g); taking 3mL of supernatant fluid into a new 4mL centrifuge tube; drying in 50 deg.C water bath with nitrogen; then 2mL of n-hexane is added, the mixture is fully swirled for 30s, 1mL of sample diluent (pH7.4 PBS: NaCl 8g, KCl 0.2g, Na2HPO 4.12H2O 3.58.58 g, KH2PO40.24g, deionized water is added to the volume of 1L), and the mixture is swirled at a low speed for 30 s; centrifuging for 5min at a speed of more than 4000 g; completely removing the upper n-hexane layer and the intermediate layer impurities; 100 μ L of the sample was taken as a sample solution to be tested.

2) And a detection step

And (3) dropwise adding 100 mu L of sample solution to be detected onto a sample pad of the prepared quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card (shown in figure 1), accurately reacting in a detection card constant-temperature incubator at 40 ℃ for 5min, taking out, and detecting by using a fluoroimmunoassay quantitative analyzer.

If the fluorescence signal value of the detection line T is less than or equal to the fluorescence signal value of the quality control line C, the to-be-detected sample contains or is candidate to contain quinolone drugs;

and if the fluorescence signal value of the detection line T is greater than that of the quality control line C, the to-be-detected sample does not contain or candidate does not contain quinolone drugs.

2. Establishment of quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card quantitative detection method (TRFIA)

1) Drawing of standard curve

Taking a yak meat negative sample (LC-MS/MS detection does not contain quinolone drugs, and the content is lower than the detection limit of an instrument method), and respectively adding quinolone drug standard solutions (specifically ciprofloxacin standard solutions) into the yak meat negative sample to ensure that the final concentrations of ciprofloxacin are respectively: 0.00. mu.g/kg, 0.25. mu.g/kg, 0.5. mu.g/kg, 1. mu.g/kg, 2. mu.g/kg and 4. mu.g/kg, and then sample extraction was performed according to the method described in 1 above to obtain extracts of samples at respective concentrations.

The extract solutions of the samples of the respective concentrations were detected in accordance with 2) of the above 1. The assay was repeated 5 times for each concentration and averaged. Taking the final concentration of ciprofloxacin added in a sample as an X axis, taking the ratio (T/C) of the fluorescence signal value of a detection line T and the fluorescence signal value of a quality control line C as a Y axis, and carrying out nonlinear fitting analysis by using origin8.0(origin Lab Corp., Northampton, MA, USA). The fitting of test data shows that the standard curve of the established ciprofloxacin time-resolved fluorescence immunochromatographic assay quantitative detection method corresponding to the yak meat sample is as follows:

Y＝0.399+(7.393-0.399)/(1+(x/0.465)^1.46)，R²0.9940 (FIG. 2).

Wherein X is a ciprofloxacin concentration value, and Y is a T/C value.

^1.46 denotes the power of 1.46.

2) Sample extract

Preparing a sample solution to be tested according to 1) in the step 1).

3) And detecting

And (3) dropwise adding 100 mu L of sample to-be-detected liquid onto a sample pad in the prepared quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card, accurately reacting in a detection card constant-temperature incubator at 40 ℃ for 5min, taking out, and detecting by using a fluoroimmunoassay quantitative analyzer to obtain a T-line fluorescent signal value and a C-line fluorescent signal value.

Substituting the ratio of the fluorescence signal value of the T line to the fluorescence signal value of the C line into the standard curve of the 1) to obtain the content of the quinolone drugs in each sample.

Third, the minimum detection limit of the quinolone drug time-resolved fluoroimmunoassay rapid detection reagent card

And 20 parts of yak meat negative samples (LC-MS/MS detection negative) respectively.

And (3) detecting the content of the quinolone drugs in the 20 negative samples according to the method 2 in the second step. The mean and standard deviation of ciprofloxacin content were calculated separately: the mean value plus 9 times standard deviation is the limit of quantitation.

TABLE 2 time-resolved fluorescence immunochromatography detection limit verification (μ g/kg)

As a result, as shown in Table 2, it can be seen that the minimum detection limit of the drug was 0.4963. mu.g/kg by establishing a standard curve using ciprofloxacin as a control. In order to ensure the accuracy and reliability of the result, the quantification of ciprofloxacin in yak meat is limited to 0.5 mug/kg.

Fourth, accuracy and precision

Respectively adding 20 parts of each yak meat negative sample (LC-MS/MS detects that the content of quinolone drugs is lower than the detection limit of the method), respectively adding ciprofloxacin, oxolinic acid, danofloxacin, norfloxacin, flumequine, enoxacin, enrofloxacin and ofloxacin standard solutions, wherein the concentration of the drugs added to the samples is the corresponding quantitative limit and 2 times of the quantitative limit, adding 5 drugs in each concentration gradient in parallel, and calculating the addition recovery rate of the samples and the variation coefficients of the samples in batches and in batches.

And detecting according to the two methods, and finally analyzing the accuracy and precision of the established time-resolved fluorescence immunochromatographic quantitative analysis method according to the added recovery data.

The result is shown in table 3, the addition recovery rate of the quinolone drugs in the yak meat is 86.08-106.96%, and the intra-batch and inter-batch variation coefficients are less than 15%, which shows that the method has better accuracy and precision.

TABLE 3 accuracy and precision of time-resolved fluoroimmunoassay in quinolone drug samples

The recovery rate was (average value/added concentration) × 100%

Coefficient of variation ═ (standard deviation/average) × 100%;

fifthly, comparing the detection result of the quinolone drug time-resolved fluorescence immunoassay rapid detection reagent card (TRFIA) with the detection result of LC-MS/MS

And (3) detecting yak meat samples (total 100 parts) by using the method II (TRFIA), and respectively carrying out confirmation comparison on detection results of LC-MS/MS. And (3) detecting the remaining 9 positive samples and the suspicious samples, and drawing a scatter diagram by taking the concentration of the carbostyril drug measured by TRFIA as an X axis and the concentration of the carbostyril drug measured by LC-MS/MS as a Y axis. The measurement results of the two methods were subjected to linear analysis, and the results are shown in fig. 3, and the regression equation is: y is 0.942+0.089x, R²0.9744, the established TRFIA and the LC-MS/MS detection result have good consistency.

Sixthly, a detection method for comparing a quinolone drug time-resolved fluorescence immunoassay rapid detection reagent card (TRFIA) and other methods

In order to detect the quinolone drugs in the yak meat more efficiently, a time-resolved fluorescence immunochromatographic method is established and compared with other methods, and the comparison result is shown in table 4.

TABLE 4 ciprofloxacin detection method comparison

The references are specifically as follows:

[1] the method for determining 11 quinolone drug residues in yak meat by using a super performance liquid chromatography-mass spectrometry tandem method comprises the steps of determining 11 quinolone drug residues [ J ] in the yak meat, performing medical animal control, 2018,34(06):570-573.

[2] The method comprises the steps of (1) sequencing the Zong (tuberculosis) cells, Zhang Xiaojun, Yanzhong Yong, and the like.

[3] Xieshiwan, Wangweimna, Mengxiang, etc. the development of carbostyril colloidal gold detection reagent plate and its application in aquatic products [ J ] Jiangsu agricultural science, 2018(1): 185-187).

[4] Zhengbaiqin, luo xiao qin, Feng cai, etc. development of enzyme-linked immunosorbent assay rapid detection kit for quinolone drugs [ J ] brewing in China, 2014,33(02): 130-.

SEQUENCE LISTING

<110> Beijing Weideweikang Biotech Co., Ltd, animal epidemic prevention control center of Qinghai province

Time-resolved fluorescence immunochromatographic assay quantitative detection method for quinolone drugs in yak meat

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<170>PatentIn version 3.5

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Gly Pro Phe Pro Arg Ala Val Val Thr Gln Glu Ser Ala Leu Thr Thr

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Ser Thr Thr Thr Ile Tyr Ala Glu Leu Gly Pro Arg Lys Thr Arg Ser

35 40 45

Phe Ile His Trp Ser Asn Arg Cys Tyr Cys Gln Pro Ser Ser Arg Cys

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Ser Cys Gln Ile Leu Arg Leu Pro Asp Trp Arg Gln Gly Cys Pro His

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His His Arg Gly Lys Asp Leu Arg Gln Tyr Ile Ser Val Leu Tyr Gly

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Thr Ala Thr Ile Ser Thr Met Thr Cys Val Asp Gly Glu Val Glu Gln

100 105 110

Glu His Ser Gly Thr Val Ser Ile Thr Thr Thr Phe Leu Thr Gly Gly

115 120 125

Tyr Ile Ser Leu Val Cys Ser Leu Leu Leu Leu Glu Lys Phe Ile Lys

130 135 140

Ala Val Val Ser Ile Asn Lys Lys Phe Tyr Phe Asn Lys Leu Tyr Asn

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Tyr Ala Leu Met Thr Ser Phe Val Tyr Gln Leu Gly Thr Thr Leu Glu

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Leu Pro Ala Val Met Leu Ser Thr Pro Lys Leu His Ser Pro Cys Leu

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20 25 30

Ser Thr Tyr Asn Ser Leu His Leu Phe Arg Met Val Pro Ala Glu Thr

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Arg Pro Val Ser Lys Ala Pro Asp Leu Arg Leu Ser Asn Arg Leu Ser

50 55 60

Gly Val Pro Asp Arg Phe Ser Gly Ser Gly Ser Gly Thr Asp Phe Thr

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Leu Lys Ile Ser Arg Val Glu Ala Glu Asp Leu Gly Val Tyr Tyr Cys

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Phe Gln Gly Ser His Val Pro Pro Thr Val Ile Gln Thr Leu Thr Lys

100 105 110

Ile Val Leu Leu Trp Val Ser Gln Leu Leu Asn Met Leu Phe Met Phe

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Glu Arg Gly Ser Glu Gly Leu Gln Phe Ile Ser His Ala Glu Gly Lys

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Claims (10)

1. A quinolone drug time-resolved fluorescence immunoassay reagent card comprises a bottom plate, a sample pad, a release pad, a nitrocellulose membrane and a water absorption pad, wherein the sample pad is arranged on the bottom plate, the release pad contains an europium microsphere labeled anti-quinolone drug antibody, the nitrocellulose membrane contains a quinolone drug detection line T and a quality control line C, and the nitrocellulose membrane contains a water absorption pad.

2. The reagent card of claim 1, wherein: the anti-quinolone drug antibody is an anti-ciprofloxacin monoclonal antibody;

the amino acid sequence of the light chain variable region of the ciprofloxacin-resisting monoclonal antibody is 1;

the amino acid sequence of the heavy chain variable region of the ciprofloxacin-resisting monoclonal antibody is 2.

3. The reagent card of claim 2, wherein:

the release pad containing the europium microsphere labeled anti-quinolone drug antibody is formed by spraying an europium microsphere labeled anti-ciprofloxacin antibody solution on the release pad;

the coating concentration of the europium microsphere-labeled anti-ciprofloxacin antibody solution is 1.4 mg/mL.

4. The reagent card of claim 3, wherein: in the europium microsphere-labeled ciprofloxacin antibody solution, the mass ratio of the ciprofloxacin antibody to the europium microsphere is 7: 20;

or the europium microspheres are 200nm carboxylated europium microspheres.

5. The reagent card of any one of claims 1-4, wherein:

the quinolone drug detection line T is formed by ciprofloxacin antigen or a solution thereof;

or the coating concentration of the ciprofloxacin antigen solution is specifically 1.0 mg/mL;

or, the quality control line C is formed from an IgG antibody or an IgG antibody solution;

or the coating concentration of the IgG antibody solution is specifically 0.875 mg/mL;

or, the nitrocellulose membrane containing the quinolone drug detection line T and the quality control line C is a nitrocellulose membrane coated with the ciprofloxacin antigen solution to form the detection line T, and the IgG antibody solution is coated with the nitrocellulose membrane to form the quality control line C, so as to obtain the nitrocellulose membrane containing the quinolone drug detection line T and the quality control line C.

6. A method of making a reagent card according to any one of claims 1 to 5, comprising the steps of: firstly, preparing a release pad containing an europium microsphere-labeled anti-quinolone drug antibody and preparing a nitrocellulose membrane containing a quinolone drug detection line T and a quality control line C; assembling a sample pad, the release pad containing the europium microsphere-labeled anti-quinolone drug antibody, the nitrocellulose membrane containing the quinolone drug detection line T and the quality control line C and the water absorption pad on a bottom plate to obtain a reagent card;

the europium microsphere-labeled anti-quinolone drug antibody-containing release pad is formed by spraying europium microsphere-labeled anti-quinolone drug antibody solution on the release pad;

the concentration of the europium microsphere-labeled anti-ciprofloxacin antibody solution is 1.4 mg/mL;

the anti-quinolone drug antibody is an anti-ciprofloxacin monoclonal antibody;

the amino acid sequence of the light chain variable region of the ciprofloxacin-resisting monoclonal antibody is 1;

the amino acid sequence of the heavy chain variable region of the ciprofloxacin-resisting monoclonal antibody is 2;

the quinolone drug detection line T is formed by ciprofloxacin antigen or a solution thereof;

or the coating concentration of the ciprofloxacin antigen solution is specifically 1.0 mg/mL;

the quality control line C is formed by IgG antibody or IgG antibody solution;

or the concentration of the IgG antibody solution is specifically 0.875 mg/mL;

the cellulose nitrate membrane containing the quinolone drug detection line T and the quality control line C is formed by coating ciprofloxacin antigen solution on the cellulose nitrate membrane to form the detection line T, and coating IgG antibody solution on the cellulose nitrate membrane to form the quality control line C, so that the cellulose nitrate membrane containing the quinolone drug detection line T and the quality control line C is obtained.

7. Use of a reagent card according to any one of claims 1 to 6 in the preparation of a quinolone pharmaceutical product for testing or for aiding in testing;

or the use of the reagent card according to any one of claims 1 to 6 for the preparation of a test or for the auxiliary detection of a quinolone drug product in a test sample;

or the use of the reagent card according to any one of claims 1 to 6 for the preparation of a product for detecting or for the auxiliary detection of the content of quinolone drugs in a sample to be tested;

or the use of said reagent card of any of claims 1-6 for the detection or assisted detection of quinolone drugs;

or the use of the reagent card according to any one of claims 1 to 6 for the detection or the auxiliary detection of the presence of a quinolone drug in a sample to be tested;

or the use of the reagent card according to any one of claims 1 to 6 for the detection or assisted detection of the quinolone drug content in a sample to be tested;

or the europium microsphere-labeled anti-ciprofloxacin antibody in the reagent card of any one of claims 1 to 6, for detecting or assisting in detecting whether a quinolone drug is contained in a sample to be detected or the content of the quinolone drug in the sample to be detected.

8. A method for detecting or assisting in detecting whether a sample to be detected contains quinolone drugs or not comprises the following steps: extracting a sample to be detected by using an organic solvent, and collecting an extracting solution; adding the extracting solution to a sample pad of the reagent card of any one of claims 1 to 6, reacting, and detecting the reaction product by using a fluorescence immunoassay analyzer;

the organic solvent comprises acetonitrile and n-hexane;

if the fluorescence signal value of the detection line T of the reagent card is less than or equal to the fluorescence signal value of the quality control line C, the to-be-detected sample contains or is candidate to contain quinolone drugs;

and if the fluorescence signal value of the detection line T of the reagent card is greater than the fluorescence signal value of the quality control line C, the sample to be detected does not contain or candidate does not contain quinolone drugs.

9. A method for detecting or assisting in detecting the content of quinolone drugs in a sample to be detected comprises the following steps:

1) preparing a standard curve;

taking a sample which has the same source as a sample to be detected and does not contain the quinolone medicaments, adding the quinolone medicaments with different concentrations, extracting the sample by using an organic solvent, and collecting extract containing the quinolone medicaments with different concentrations; the organic solvent comprises acetonitrile and n-hexane;

adding the extracting solutions with different quinolone drug concentrations to the sample pad of the reagent card in any one of claims 1 to 6, reacting, and testing by using a fluorescence immunoassay quantitative analyzer to obtain detection line T fluorescence signal values and quality control line C fluorescence signal values of standard solution with different concentrations;

taking different concentrations of added quinolone drugs as an X axis, taking the ratio of the fluorescence signal value of the corresponding detection line T to the fluorescence signal value of the quality control line C as a Y axis, and drawing a standard curve;

2) extracting a sample to be detected by using an organic solvent, and collecting a sample extracting solution to be detected; the organic solvent comprises acetonitrile and n-hexane;

adding the extracting solution of the sample to be detected on the sample pad of the reagent card of any one of claims 1 to 6, reacting, and detecting the reaction product by using a fluorescence immunoassay analyzer to obtain the fluorescence signal value of the detection line T and the fluorescence signal value of the quality control line C of the sample to be detected;

substituting the fluorescence signal value of the detection line T and the fluorescence signal value of the quality control line C of the sample to be detected into the standard curve obtained in the step 1) to obtain the content of the quinolone drugs in the sample to be detected.

10. The use according to claim 7 or the method according to claim 8 or 9, characterized in that: the quinolone drugs are ciprofloxacin, oxolinic acid, danofloxacin, norfloxacin, flumequine, enoxacin, enrofloxacin or ofloxacin.

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