“Non-target screening strategies for identification of transformation products after abiotic degradation and biotransfo rmation processes”

MARIA VITTORIA BARBIERI; DORDETADIC ; LUCAS G SOSA ALDERETE ; ANDRÉS SAUVÊTRE; SERGE CHIRON

Workshop; ?18th Annual Workshop On Emerging High-Resolution Mass Spectrometry (Hrms) And Lc-Ms/Ms Applications In Environmental Analysis And Food Safety?; 2022

The widespread use of chemicals worldwide is increasing and new contaminants constantly appear in the environment. Recent advances in analytical techniques include the combination of gas chromatography (GC) or liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) for the detection of a wide range of contaminants and transformation products (TPs) using suspect screening analysis (SSA) or non-target screening analysis (NTA). The analytical workflow for non-target methods depends on several factors, such as the aim of the study, groups of contaminants or type of matrix. Currently, there is no standard protocol for data processing and TPs identification, and a series of different steps for data interpretation can be employed. In many cases, phase I and phase II of metabolization pathways involve biotransformation reactions, which may differ from abiotic photodegradation, especially in phase II. Hence, the strategies applied to identify TPs have to be addressed accordingly. In this work, we discuss different data acquisition and data treatment strategies to be used for the analysis, prioritization and identification of unknown TPs coming from emerging contaminants, based on either biodegradation systems using hairy roots or natural degradation processes (e.g. photodegradation). In suspect screening, it is of the utmost importance to correctly compile a list of potential candidates that should be based on the expected transformation reactions. To this end, in-depth TPs identification and confirmation consisting of in-silico predicted transformation reaction and non-target screening using Compound Discoverer have been employed in both plant-system and photolysis transformation, respectively. Results showed the identification of 10 to 15 TPs of each antibiotic in plant-based system, most of them generated after phase I and phase II as result of oxidation and conjugation reactions, respectively. Photolysis experiments shared phase I reactions as in plant-system and not phase II, with typical photo-transformation reactions that could not be identified in plant-system, as is the case of substitution reactions.