Abstract:[Objective] This study aims to establish a pre-treatment method with only one time of operation for simultaneous and rapid detection of seven veterinary drug residues in pork. [Method]Seven veterinary drugs (dexamethasone, chloramphenicol, thiamphenicol, florfenicol, sulfamethazine, metronidazole, and tylosin) in pork were studied. A unified pre-treatment method was established after integration, optimization, and testing based on colloidal gold immunochromatographic assay products from major rapid detection brands for veterinary drugs in China. The performance indicators including limit of detection, sensitivity, false positive rate, and false negative rate of the established method were investigated. The colloidal gold immunochromatographic assay products from other manufacturers in the market were used to verify the universality of the established method. [Result]The optimal extraction system was saturated sodium chloride solution-ethyl acetate. The preferred purification method was n-hexane degreasing. Phosphate buffered saline (pH 7.2, 0.02 mol/L) containing 3% (volume fraction) methanol was selected as the solution for drug reconstitution. The limits of detection of the seven veterinary drugs in pork were determined as follows: 1.0 μg/kg for dexamethasone, 0.10 μg/kg for chloramphenicol, 50 μg/kg for thiamphenicol, 300 μg/kg for flurfenicol, 100 μg/kg for sulfamethazine, 0.50 μg/kg for metronidazole, and 100 μg/kg for tylosin. The sensitivity, false positive rate, and false negative rate of the established method was 96%, 6%, and 4%, respectively. [Conclusion] The detection results of this method were highly consistent with the reference methods. And this method can be used for colloidal gold immunochromatographic assay products for rapid detection from other manufacturers. This method, with high accuracy, rapid detection, simple operation, high efficiency, and a low cost, can meet the needs of on-site and large-scale screening of multiple veterinary drug residues in pork.
