Development Of Fluorescence Immunochromatographic Assay For Detection Of Tetracycline

In this work,a quantum dot based immunochromatographic assay(QDICA),a fluorescence quenching immunochromatographic assay(FQICA),and a fluorescence microsphere based immunochromatographic assay(FMICA)are developed to quickly detect tetracycline antibiotics residues in foods.The visual test results from QDICA can be obtained under UV light by naked eye.In the QDICA,the quantum dots labeled anti-tetracycline antibody complex(QDs-Ab)acts as fluorescence signal probe,the sample diluent is pH 7.4 PBS,the dilute ratio of the goat anti mouse IgG sprayed on the control line(C line)is 1:10,the dilute ratio of the coating antigen(TC-BSA)sprayed on the test line(T line)is 1:100,the added dosage of QDs-Ab is 1μL,and the added dosage of working buffer is 6 μL.The visual limit of detection of QDICA is 5 μg L-1,and the test time is 10 min.For milk,shrimp,grass carp,weever,carp,pork,chicken and beef,the limits of detection are 50 μg kg-1.The FQICA is based on a dual-functional visual test mode,the fluorescent test results under UV light and the colorimetric test results under natural light can be obtained by naked eye.In the FQICA,the quantum dots labeled OVA complex(QDs-OVA)acts as fluorescence signal probe,and the colloidal gold labeled anti-tetracycline antibody complex(AuNPs-Ab)acts as quencher,the sample diluent is pH 7.4 PBS,the dilute ratio of the QDs-OVA sprayed on the C line is 1:8,the dilute ratio of the diluted QDs-OVA and TC-BSA sprayed on the T line is 1:50,the added dosage of AuNPs-Ab is 2 μL,and the added dosage of working buffer is 3 μL.The visual limits of detection of QDICA are 2 μg L-1 under the UV light and 10 μg L-1 under natural light,the test time is 10 min.For shrimp,grass carp,weever,carp,pork,chicken,and beef,the limits of detection are 40 μg kg-1 under UV light and 200 μg kg-1 under natural light.For milk,the limits of detection are 20μg L-1 under UV light and 100 μg L-1 under natural light.At the same time of obtaining visual qualitative test results,the utilize of the difference between the visual limits of detection under two test modes can achieve semi-quantitative detection of tetracycline antibiotics and judge of limits of tetracycline antibiotics are violated or not.The FMICA can achieve quantitative detection of tetracycline antibiotics by portable fluorescence readout.In the FMICA,the fluorescence microspheres labeled anti-tetracycline antibody complex(FMPs-Ab)acts as fluorescence signal probe,the sample diluent is pH 7.4 PBS,the dilute ratio of the goat anti mouse IgG sprayed on the C line is 1:30,the dilute ratio of the TC-BSA sprayed on the T line is 1:20,the added dosage of FMPs-Ab is 2 μL,and the added dosage of working buffer is 10 μL.The quantitative limit of detection of the FMICA is 0.2μg L-1,and the test time is 10 min.For shrimp,chicken,and pork,the quantitative limit of detection is 8 μg kg-1.For milk,the quantitative limit of detection is 16 μg L-1.