In a presentation filmed during NACRW 2016, Professor Amadeo Fernández-Alba, University of Almeria, evaluated the Thermo Scientific™ Q Exactive™ GC Orbitrap GC-MS/MS System for the multiresidue analysis of pesticides in fruits and vegetables. Professor Fernández-Alba heads the European Reference Laboratory for Pesticide Residues in Fruits and Vegetables, a cooperation linking laboratories across Europe, which aims to improve pesticide residue analysis.
Using optimized GC-MS conditions, his team evaluated 210 different pesticides in in easy and difficult SANTE 11945/2015 guidelines, including tomato, orange and leek. The list of pesticides included all of the GC-amenable pesticides in the Multiannual Control Programme in Europe. The electron ionization, full scan, data acquired at 60,000 resolving power, 1-2 ppm mass accuracy, provided quantitation and identification performance similar and in some cases better than GC- triple quadrupole MS systems. Amadeo commented that the Orbitrap GC-MS system routinely achieved detection limits of 10 ppb over a linear range up to 500 ppb, with precision of 20% RSD or less, for the majority of pesticide-commodity combinations, so that the data are essentially in full compliance with the SANTE 11945/2015 guidelines.
Professor Fernández-Alba stated that another benefit to using full-scan acquisition workflows is that the acquired data can be used for both target and non-target data processing. The decision is made after acquisition and is dependent on the software, libraries, and databases used for data processing. Users can either create their own databases using theoretical masses, or use existing libraries such as the NIST library. Non-targeted acquisition allows retrospective analysis and also screening for obsolete pesticides and pesticides for which standard reference materials are extremely expensive or not commercially available. Even pesticide transformation products that are produced by the analytical method can be detected. He concluded that overall the Exactive™ GC Orbitrap™ GC-MS was a robust system and should provide improved efficiency and accuracy of screening workflows in routine laboratories.