In this work a method for the determination of 15 pesticides in bread samples using gas chromatography coupled with mass spectrometry (GC-MS), operating in the negative chemical ionization mode (NCI) was developed and validated. For the extraction procedure acetonitrile containing 1% (v/v) acetic acid was used in presence of sodium acetate, sodium citrate and magnesium sulphate. The method was validated evaluating the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy. The linear range used was from 1.0 to 100 µg L-1. The recoveries had been considered satisfactory presenting values between 70 and 117% with RSD < 17.6% for almost all the compounds. The real method LOQ ranged from 10 to 20 µg kg-1. The method shown to be adequate for the multiresidue analysis of pesticides in bread and the GC-MS (NCI) proved to be sensitive and highly selective.
pesticides; multiresidue; bread; GC-MS
