Abstract
This study evaluated the matrix effect (ME) in a multiresidue analysis with the modified official Japanese method for agricultural products using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In ME comparisons between the vegetable and fruit samples, it was found that more numerous analytes exhibited ion suppression in the vegetable samples than in the fruit samples, and substantial ion enhancement was not observed in most of the analyte-sample combinations. The ME could significantly vary, even within the same commodity, and it was suggested that sampling has greater influence than measurement when there is a wide ME variability. Dilution, the internal standard calibration method and the matrix-matched calibration method are practical countermeasures against MEs, but certain limitations in their applications should be considered. Moreover, a novel cleanup procedure suitable for hydrophilic neonicotinoid pesticides that minimized the usage of expensive internal standard solutions was suggested.