A Highly Sensitive Detection Method for Five Organophosphorus Pesticide Residues in Tea Based on the Combined Technology of SPME-LC-MS/MS

Excessive pesticide residues seriously threaten the safety of agricultural products and the health of consumers. As a widely consumed beverage, the monitoring of pesticide residues in tea is of vital importance. To improve the sensitivity and accuracy of organophosphorus pesticide residue detection in tea, an integrated method combining solid-phase microextraction pretreatment and high-performance liquid chromatography-tandem mass spectrometry analysis was researched and developed. The research optimised the sample pretreatment process. Tea powder was extracted by vortex using a mixed solvent of ethyl acetate and n-hexane with a volume ratio of 9 : 1. The isotope internal standard method was used for quantification. By optimising the chromatographic conditions and mass spectrometry parameters, the detection methods for five target pesticides were established, and the linear range, quantification limit, accuracy and precision of the methods were systematically evaluated. The results show that the linear relationship of the five organophosphorus pesticides is good within the range of (5.0 - 500.0) ng/mL, and the quantitative limit of the method is extremely low, ranging from 0.0011 mg/kg to 0.0026 mg/kg. The correlation coefficients of the standard curves were all greater than 0.99, and the average recovery rates ranged from 72 % to 109 %. The results show that the pretreatment of the research method is simple, rapid and has low solvent consumption, effectively improving the detection efficiency and accuracy. The research provides efficient and reliable analytical means for ensuring the quality and safety of tea, safeguarding consumers’ health and promoting the sustainable development of the tea industry.