Matrix Effect Evaluation and Method Validation of 181 Pesticides in Three Types of Tea Using Gas Chromatography-Tandem Mass Spectrometry

The difference of matrix effects caused by different types of tea in the analysis of pesticide residues using gas chromatography-tandem mass spectrometry (GC-MS/MS) has not been well studied. This study evaluated the matrix effects of 181 pesticides in three types of tea with different fermentation degrees using GC-MS/MS. The matrix effect of pesticides detected in black tea was significantly lower than that in green tea and dark tea, with a particularly pronounced matrix enhancement effect. The median values of the matrix effects of 181 pesticides for green tea, black tea and dark tea were 179%, 17% and 197%, respectively. A GC-MS/MS method for 181 pesticide residues in tea was validated using the matrix-matched standard prepared using blank tea sample with a fermentation degree similar to that of the test samples. The results showed that the recoveries of more than 95% pesticides were in the range from 60–120% with the relative standard deviation less than 25%. The limits of quantitation (LOQs) spanned a range from 5 µg/L to 100 µg/L. When this method was applied to the residue detection of actual samples, it could effectively reduce the deviation within the range of 2.21–100%. It is recommended that the matrix matched standard solution should be prepared using blank tea with similar fermentation degree to the test sample in the analysis of pesticide residues in different types of tea using GC-MS/MS.