Three approaches to minimize matrix effects in residue analysis of multiclass pesticides in dried complex matrices using gas chromatography tandem mass spectrometry

This paper discusses one of the major concerns in pesticide residue analysis: the matrix effect related to gas chromatography (GC), which can adversely affect quantification. In this study, a comparison of approaches for dealing with the matrix effect was investigated for 236 pesticides in complex matrices, including dried herbs (Centaurea cyanus L., Matricaria chamomilla L., Thymus vulgaris L.) and dried fruit (currants, chokeberry), using a modified QuEChERS method and GC-MS/MS analysis. Three approaches were evaluated: (i) using matrix-matched calibration, (ii) adding a mixture of analyte protectants (APs) to every extract or (iii) injection prior to GC-MS/MS analysis. Finally, minimization of the matrix effect to the acceptable levels of -20 to 20% for over 80% of investigated pesticides was found when APs mixture was injected at the beginning of the sequence. In this approach, the matrix effects were significantly weaker for some pesticides than when matrix-matched calibration was used.