Determination of 195 pesticide residues in Chinese herbs by gas chromatography–mass spectrometry using analyte protectants

The phenomenon known as “matrix-induced enhancement effect” is not only observed in the analysis of pesticides in food, but also in Chinese herbs. Several approaches have been proposed to overcome the matrix-induced effect, but each method has serious limitations. Compared with standard calibration methods, the procedure with adding analyte protectants offers a more convenient and effective route to solve the problem. In the current study, we have analyzed 195 types of pesticides in Chinese herbs by gas chromatography–mass spectrometry (GC–MS), and the compounds that are susceptible to matrix effect were picked up and confirmed. In addition, several analyte protectants were evaluated and the most effective combination was determined. d-Ribonic acid-γ-lactone (2 mg/ml) and d-sorbitol (1 mg/ml) were shown to be the best analyte protectants for the analysis of most pesticides.