Impact of pesticide formulation excipients and employed analytical approach on relative matrix effects of pesticide determination in strawberries.

Relative matrix effects between an ambient mass spectrometric technique known as coated blade spray (CBS) and liquid chromatographic separation approach when applied to multiresidue pesticide analysis in strawberry samples are explored. Acceptable slope relative standard deviations (RSD <15 %) were observed for the 9 compounds under study for both CBS-MS/MS (2.2-12.6 %) and LC-MS/MS (2.8-12.9 %) approaches. The findings signify both the elimination of relative matrix effects with the sample preparation and matrix match calibration with internal standard correction methods employed along with no matrix effect compromise made when using the direct-to-MS approach. Similarly, slopes of pesticides spiked from commercially available formulations (containing one or two pesticides) were found to not differ significantly from slopes generated with multiresidue pesticide standards (containing 24 additional pesticides besides the target 9 analytes) with either technique, highlighting the resistance of the employed methods to the excipients present in pesticide formulations in large amounts.