Determination of 70 pesticide residues in tobacco leaves based on EMR-Lipid dispersive solid-phase extraction combined with gas chromatography-tandem mass spectrometry.

The objective of this study was to establish an effective sample preparation protocol for the determination of pesticide residues in tobacco. Two distinct cleanup approaches were evaluated: the classical QuEChERS method and a protocol utilizing EMR-Lipid. All prepared samples were analyzed via gas chromatography-tandem mass spectrometry (GC-MS/MS), and the optimally selected approach was subjected to method validation. This is the first study to use EMR-Lipid as a dispersive solid-phase extraction (d-SPE) sorbent for pesticide detection in tobacco. Compared with the conventional PSA-based cleanup approach, the EMR-Lipid method substantially alleviated matrix interference, reducing the number of pesticides exhibiting high matrix effects from 30 to 11. It also improved recovery performance, with 94% of the target pesticides showing recoveries within 70-110% at the 0.5 mg kg-1 spiking level. Validation experiments for the EMR-Lipid method showed good linearity, with coefficients of determination (R2 > 0.99). The limits of quantification (LOQs) ranged from 2.0 to 10.0 µg kg-1. The RSDs for all selected pesticides ranged from 0.7% to 15.9%. This method was applied for the first time to determine pesticide residues in tobacco samples from Jiangxi Province, China. The methodology demonstrated acceptable accuracy and precision for multi-residue analysis.