Identification and quantitation of pesticides in vegetables by liquid chromatography time-of-flight mass spectrometry

Abstract

This overview covers pesticide-residue determination in food samples by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). We present the application of LC-TOF-MS in terms of accuracy, sensitivity and robustness for the quantitative analysis of pesticides in fruit and vegetable samples. The analytical performance of the methodology is validated for various types of vegetables matrices. Accurate mass measurements (with accuracy better than 3 ppm error) for both the (de)protonated molecule and characteristic fragment ions together with the high-resolution chlorine isotopic signature present in a large number of pesticides and the retention time represent reliable identification criteria for these species in such complex samples. We demonstrated linearity of response over two orders of magnitude ( r > 0.99) with no significant matrix effects (less than 30%). Low limits of detection at the low mg/kg level, depending on the commodity and pesticide studied, were obtained, all within European Union regulations for food-monitoring programs. The high degree of confirmation for target pesticides by accurate mass measurements demonstrated the applicability of TOF-MS techniques in routine analysis. This overview is a valuable indicator of the potential of LC-TOF-MS to provide high-order structural information for the unequivocal identification of both targeted and non-targeted pesticide residues present in fruit and vegetables.