OBJECTIVETo establish a novel suspension microarray technology for the detection of three kinds of veterinary drug residues: chloramphenicol, clenbuterol and 17-beta-estradiol (CAP, CL and E2).

METHODSThe three conjugates that veterinary drug coupled with bovine serum albumin (BSA) were synthesized and identified by ultraviolet (UV) spectrophotometry and mass spectrum. The veterinary drug conjugates were immobilized on the polystyrene fluorescent microspheres/beads. There were competitive reactions between the veterinary drugs in the aqueous phase and that on the beads for combination with their specific biotinylated monoclonal antibodies. The optimum amount of the veterinary drug conjugates and the antibodies were optimized and selected. The detective standard curves were plotted. The specificity and the unknown samples were also determined by grouping according to different concentrations of the interferes and the samples. Meantime, the different microstructures of the surfaces of the beads were also observed by scanning electron microscope.

RESULTSCouplings were completed between small molecular veterinary drugs and BSA. The amounts of the three conjugates and the antibodies were optimized. The detective standard curves of the suspension array and their corresponding coefficients of determination (R2) were good (R2 > 0.99). The detection ranges of the three veterinary drugs were (40.00 - 6.25) x 10(5) ng/L, (50.00-7.81) x 10(5) ng/L and 1.00 x 10(3) - 7.29 x 10(5) ng/L respectively. Simultaneously, the specific detection of the suspension microarray was excellent and did not indicate significant cross-reactions. Errors between the found and the real are in the range of 8.09% - 17.03%. It can be considered that the relative standard deviations were relatively small. Successful couplings were also directly confirmed by the observation for microstructures of the surfaces of the beads by scanning of electron microscope and laid good foundation for the following responses.

CONCLUSIONThe high-throughput suspension microarray should provide a novel method for multi-analysis of the veterinary drugs and have a wide applicative prospects with simple operation, sensitive, rapid and low cost.