Efficiency of ESI and APCI ionization sources in LC-MS/MS systems for analysis of 22 pesticide residues in food matrix.

The intensive use of pesticides has led to the need to optimize analytical methodologies for the control of residues in food. The present study aims to compare the efficiency of different ion sources (Eletrospray Ionization-ESI and Atmospheric Pressure Chemical Ionization - APCI) in LC-MS/MS systems, when analysing 22 pesticides in a cabbage matrix. The method performance was evaluated during a validation study. Organophosphates, triazoles, pyrethroids and triazines compounds showed good linearity in the range 0.5-200 μg.Kg. Statistical tests were used to evaluate linearity. LOQm values varied from 0.50 to 1.0 μg.Kg to the ESI source, and 1.0-2.0 μg.Kg for the APCI source. Matrix effect was more intense when using the APCI source. Accuracy and precision were evaluated at three levels of concentration (2; 20 and 100 μg Kg). Most of the compounds presented recovery between 70 and 120%. ESI-LC-MS/MS system showed greater efficiency in multiresidue analysis in the cabbage matrix.