Detection of pesticides in popular medicinal herbs: a modified QuEChERS and gas chromatography–mass spectrometry based approach

Although a lot of work has been conducted in the pesticide residues analysis in food matrices but the quality determination (with respect to major contaminants such as pesticide residues) in medicinal plant matrices has a long way to go. Hence a study was conducted to determine pesticide residues in four medicinal herbs, which are highly traded commodities in international market. Samples were extracted and cleaned up by modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach and analyzed by gas chromatograph–mass spectrometer (GC–MS). The method was subjected to thorough validation procedure in-terms of accuracy, precision, limits of quantification (LOQ), matrix effect, linearity and uncertainty analysis. The mean recoveries for most of the pesticides were in the range of 70–120% with RSD <20% and measurement uncertainties were less than 20% for all the compounds at spiking level of 0.5 mg kg−1 in all the matrices. The limits of quantification (LOQ) ranged from 0.01 to 0.069 mg kg−1. The proposed method was successfully applied to determine pesticide residues in 52 commercial market samples obtained from different locations in India.