Determination of 523 Pesticide and Metabolite Residues in Vegetables Using Ultra-high-Performance Liquid Chromatography and Gas Chromatography Coupled to Tandem Mass Spectrometry: Method Development and Application in Monitoring Survey and Exposure Risk Assessment

A multiresidue method for simultaneously detecting 523 pesticides and metabolites in vegetables using ultra-high-performance liquid chromatography and gas chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and GC–MS/MS) was developed and rigorously validated for accuracy, precision, linearity, quantification limits, and matrix effects. The validated method was applied to analyze 300 vegetable samples from Shandong province, China, collected in 2023. Results showed the detection of 94 pesticides overall, with a detection rate of 31.67% and a 4.00% exceedance rate of maximum residue limits. Leafy vegetables exhibited the highest detection rate, and insecticides were commonly used in vegetable production. Thiamethoxam was the most frequently detected pesticide. Some banned and restricted pesticides were found at low levels. Celery, Chinese cabbage, tomato, cucumber, eggplant, sweet pepper, and spinach showed the highest frequency of multiple residues. In several rare cases, potential risks to adults and children were identified, highlighting the need for continuous monitoring of pesticide residues to ensure consumer safety.