Quest of Pesticides in Foodstuff by using High Resolution Mass Spectrometry: targeted and untargeted approach – AlimOmic

Pesticides are widely used in agriculture. Although they produce high yields, they are not without consequences for the planet and human beings. Moreover, people are increasing concern by this topic. In order to protect the human health the regulation involves maximum residue limits and monitoring and control plans. Nevertheless, recent news alerts us on the fact that no system is perfect, the case of Fipronil and the recent contamination of eggs is a perfect one drawing. Currently, liquid chromatography hyphenated to tandem mass spectrometry is recognized as the benchmark for pesticide multi-residues analysis thanks of its specificity and sensitivity. However, this technique is restricted to a pre-established list of substances to be sought a priori; so-called "targeted" approach. This lack of completeness is a problem; many molecules are likely to be found in the food, so it is important to be able to detect them. Recently, liquid chromatography hyphenated to high resolution mass spectrometry (LC-HRMS) methods appeared as a strong and promising trend in the analytical field. They allow screening a wide number of molecules and making it possible to respond to the lack of comprehensiveness of conventional analyzes and offers also the retrospective analysis of a sample. Three types of analyzes could be done on these instruments: the target screening, the suspect screening and the untarget screening. The first two used a pre-established list of compounds. Untarget screening is more about how to do peak picking by using various complex workflows and chemometrics tools without any list and a priori. Despite certain advantages of LC-HRMS method on the current approaches they have their own challenges: sensitivity of the devices to be evaluated, the criteria for identifying contaminants that require the acquisition of MS and MS² spectra, and the impact of the matrix signal and artefacts on the generation of a considerable number of features to be examined during the reprocessing of the data and finally the implementation of complex workflows requiring chemometric tools.
The AlimOmic project want to contribute to fill in the "gaps" mentioned above and by then help to disseminate the LC-HRMS approaches to monitoring laboratories in order to improve the food safety in France and aboard. It is suggested to develop and validate an analytical method on LC-HRMS to quantify, by target approach, and to detect, by untarget approach, a pool of pesticides as wide as possible (> 300 molecules). This research work will be the opportunity to evaluate the performances of such devices and approaches and also the opportunity to better understand and clarify the use and interpretation of the identification criteria due to the relative nature of each one. It will required to carry out the development of the various extracting methods necessary for the food matrices which will be analyzed (fruit, vegetables and meat) and to draw up an extensive sampling plan for two reasons. One, in order to apprehend the diversity of the matrix sampled and the generation of artefacts with the willingness to develop strategies for being able to distinguish anthropogenic (pesticide) from "natural" features and artefacts. Two, to investigate through this sampling plan the possible presence of contaminants/ pesticides not sought by conventional PSPCs and then provide data for the risk evaluation. To achieve the aforementioned objectives it will be essential to make a benchmark of the most useful and efficient workflows and software mentioned in the literature. At the end, this work should help to provide some answers to the four “gaps” mentioned earlier and also provide analytical methods and strategies to demonstrate the versatility of the approach. Finally, enable these research methods to move to routine methods and thus improve the safety and the health of consumers.