Development Of The Quantum Dot Labeled Test Strips For Detections Of Veterinary Drugs And Illegal Additions

In this study, quantum dots was selected as fluorescent label material, established two quantum dot immunochromatographic rapid test strips for the detection of quinolones and melamine. This method can be used for the rapid detection of actual samples.Used the activated ester method to synthesis quinolones coating antigen (NOR-OVA).The optimal working conditions were: The optimum pH value of the quantum dot-labeled antibody was 8.4; the molar ratio of Quantum dots to the EDC and antibody was 1:2000: 10;the dilute time of coating antigen was 1:40; the dilute time of the second antibody was 1:30;the sample solution was PBST (pH 7.4); working solution adding amount was 10 ?L; the cellulose nitrate film (NC membrane) chose Millipore HF 135s; QDs-Ab compound adding amount was 0.5 ?L. The limit detection of this test strip was 2 ng/mL, and detection time was 10 minutes. There were obvious cross reactions with other five types of quinolones:ciprofloxacin, enrofloxacin, pefloxacin, ofloxacin and lomefloxacin. There was no cross reaction with other ten types of quinolones and other five different types of Veterinary drugs, and had good specificity. The limits of detection in the actual samples were 10 ng/g.Used the activated ester method to synthesis melamine coating antigen (MEL-BSA).The optimal working conditions were: The optimum pH value of the quantum dot-labeled antibody was 8.4; the molar ratio of Quantum dots to the EDC and antibody was 1:1500:15;the dilute time of coating antigen was 1:80; the dilute time of the second antibody was 1:140; the sample solution was PBS (pH 7.4); working solution adding amount was 5 ?L;the cellulose nitrate film (NC membrane) chose Millipore HF 135s, blocked with 1% milk powder solution; QDs-Ab compound adding amount was 1 ?L. The limit detection of this test strip was 100 ng/mL, and detection time was 10 minutes. There was no cross reaction with the structural analogues except for cyclamazine. And there was no obvious cross reaction with other five different types of veterinary drugs. The limits of detection in the actual samples were 400 ng/g.There are some advantages in these two quantum dot immunochromatographic rapid test strips: samples' preparations are simple and operations are easy; having good specificities and short detection times; there are higher sensitivities compared with traditional colloidal gold test strips; being suitable for rapid detections of a large number of samples in the field.