Alternative Strategies for the Calibration and Elimination of Matrix Effects in LC-MS/MS Multiresidue Analysis of Tea Matrix

Efficiency of four different calibration techniques was evaluated on 50 pesticides in tea matrix by LC-MS/MS. Further statistical testing by MANOVA, T-tests as well as PCA indicates that calibration techniques have a significant effect on the efficiency of the analytical method to counteract the matrix effects and provide the best accuracy in the quantification. Matrix effects exceeding 20% for most of the pesticides in each calibration technique clearly indicate that matrix effects should be addressed in the calibration technique. Along with the recovery assessment, descriptive and inferential statistics proved that the procedural standard calibration technique (mean recovery of 89.3%, SD of 9.14, and standard error mean of 1.29) was the better approach than the matrix matched calibration technique. The matrix matched calibration with an internal standard, without any internal standard, and use of internal standard for some selected compounds, i.e., mix mode internal standard, were also studied.