Simultaneous determination of seven organophosphorus pesticide residues and their stability in animal-derived foods with liquid chromatography–tandem mass spectrometry

The widespread use of organophosphorus pesticides (OPs) in agriculture poses a potential risk to human health. A comprehensive method for simultaneously analyzing their residues and stability across multiple animal tissues is lacking. In this study, a liquid chromatography–tandem mass spectrometry technique was developed for the simultaneous determination of seven OPs, including trichlorfon, dichlorvos, propetamphos, fenthion, diazinon, phoxim, and malathion, in edible animal tissues. Matrix-matched calibration curves showed good linearity (R 2 >0.99). The limit of detection was 5 μg/kg (1 μg/kg for diazinon), while the limit of quantification was 10 μg/kg (diazinon 2 μg/kg). Average intra-batch recoveries were high (87.78–108.86%). Stability tests demonstrated that the standard stock solutions, working solutions, and sample extracts were stable for extended periods. Under frozen storage, trichlorfon, dichlorvos, fenthion, and malathion were prone to degradation. Notably, trichlorfon in egg white transformed into the more toxic dichlorvos at room temperature, highlighting a critical food safety risk. • Quantitative determination of seven pesticides in biological matrices was achieved. • Organophosphates standard solutions and sample extracts exhibited good stability. • Organophosphates showed poor stability in some biological samples stored at − 20 °C. • Trichlorfon in egg white degraded into dichlorvos, a more toxic compound.