Determination of 14 Pesticide Residues in Tea by QuEChERS Combined with Ultra-performance Liquid Chromatography-tandem Mass Spectrometry

A method for the determination of 14 pesticide residues in tea was developed by QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) pretreatment combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The tea samples were extracted with acetonitrile (with 1% acetic acid), purified using QuEChERS purification columns and then analyzed by UPLC-MS/MS. The effects of four purification columns on tea extracts and the recoveries of pesticide residues were compared. The column with better purification effect and recovery was selected to further investigate the matrix effect, linear relationship, and recovery of the method. The results showed that the detection limit of the method was 0.001~2.000 μg/L, and the limit of quantification was 0.003~5.000 μg/L. Reliable linear relationship within the corresponding concentration range were observed for 14 pesticides, with coefficient of determination between 0.9926 and 0.9989. The average recoveries were 71.2%~117.4% at the spiking levels of 100, 500, and 800 μg/kg with RSDs at the range of 1.1%~14.2%. This method showed its advantages of simple and fast operation, sensitivity and recovery rate, meeting the requirements for determination of multi pesticide residues in tea.