Comparison of matrix effects in multi-residue pesticide analysis when using online SPE or direct injection in Liquid Chromatography-tandem Mass Spectrometry

The multi-residue determination of pesticides is extremely challenging due to the uncertainty concerning adverse effects that those residues may have on human health after a lengthy exposure at low levels. Consequently, stricter food safety regulations are being enforced around the world, placing pesticide analysis laboratories under increasing pressure to expand the list of targeted pesticides, to detect analytes at lower levels and with greater precision, to reduce analysis turnaround times, and all the while maintaining or reducing costs. Most pesticides are generally analyzed by gas chromatography but this technique however, is not suitable for polar pesticides or thermolabile. A well established tool for the determination of residues of such pesticides is liquid chromatography combined with tandem mass spectrometry.
The aim of this study was to develop and compare two fast, sensitive and simple methodologies for the multi-residue of pesticides, that require the online SPE or direct injection in Liquid Chromatography-tandem Mass Spectrometry, thus the limits of quantification and matrix effects can be compared.