Determination of 54 Pesticide Residues in Milk by Solid-Phase Extraction Combined with Gas Chromatography-Mass Spectrometry

A high-throughput gas chromatography-mass spectrometry method was established for the analysis of 54 pesticide residues in milk. Samples were extracted with acetonitrile while shaking, and the extract was concentrated and purified using solid-phase extraction (SPE) on a C₁₈ column using acetonitrile as the eluent. The external standard method was used for quantification. The results showed that good linearity was observed over the concentration range from 0 to 1.00 μg/mL, with correlation coefficient (R²) greater than 0.990. Recoveries were between 43.33% and 113.87% with a relative standard deviation (RSD) of 1.8%-19.8% (n = 6). This method is accurate, simple and suitable for large numbers of milk samples.