Verification and Application of Biochip for Detection of Veterinary Drug Residues in Raw Milk

In order to verify the efficacy of biochip technology in the detection of veterinary drug residues in raw milk and to promote its application, 80 common veterinary drugs in raw milk were detected by biochip and confirmed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results showed that the limit of detection (LOD) of the biochip method met the requirements of the national standard, and the LOD for some veterinary drugs was below the national standard limits. The linear range of the method was wide, with correlation coefficient (r) greater than 0.99. Recoveries for negative samples spiked at 2 × and 4 × LOD concentrations were 70%–130%, with coefficient of variation (CV) of 5%–10%. This method has the advantages of simple pretreatment, short detection period and high sensitivity and is suitable for rapid screening of large quantities of samples. Using the proposed method, 10 of 100 batches of raw milk collected from Shanghai during 2022–2023 were tested positive for veterinary drug residues. Streptomyci was detected in 4 batches at concentration levels of 5.86–10.26 μg/kg, sulfapyridine in 3 batches at 1.09–1.42 μg/kg, sulfamonomethoxine in 2 batches at 1.38–1.46 μg/kg, and avermectin in 1 batch at 1.75 μg/kg. These concentration levels were far lower than the maximum residue limits set by international organizations, an announcement of the Ministry of Agriculture and Rural Affairs, and the national standard. Compared with traditional HPLC-MS/MS, the biochip method has the advantages of high sensitivity, wide linear range and fast detection rate. It can be used as a supplementary means for rapid detection of veterinary drug residues in raw milk, and has high application value.