Multi-residue analysis of pesticides and veterinary drugs by ultra-performance liquid chromatography-tandem mass spectrometry using a modified QuEChERS method

In food safety testing, simultaneous detection of multiple harmful residues is crucial because pesticide and veterinary drug residues often occur together. A method was developed for the simultaneous determination of residues of 20 pesticide and veterinary drug compounds in both buffalo and cow milk, utilizing a modified QuEChERS method combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The targeted analytes were efficiently extracted from milk matrices using a 10 % formic acid solution in acetonitrile. Optimization of both pre-treatment and analytical parameters significantly enhanced the method's sensitivity. Quantification was performed using matrix-matched calibration curves, which demonstrated exceptional linearity (R2 > 0.9990) across all analytes. Method validation, conducted with fortified blank milk samples at concentrations of 5, 10, and 50 mu g/L, yielded recoveries ranging from 73.1 % to 111.6 %. The relative standard deviations for all analytes were consistently below 15 %, confirming the method's precision. The limits of detection (LOD) and quantification (LOQ) were determined to be between 0.7 and 1.7 mu g/L and 2.0 and 5.0 mu g/L, respectively. This method is straightforward, sensitive, accurate, and environmentally friendly, making it well-suited for the detection of multiple pesticides and antibiotics in milk.