SinS - Abstract

Abstract Information :

The extensive use of antimicrobials (AMs) in agriculture has led to the emergence of residual drugs in different vegetables commonly consumed by humans, which pose a potential threat to human health due to possible effects after ingestion and the transmission of AM resistant genes. In view of the “One Health” initiative, the aim of this work was to develop a simple, sensitive and accurate analytical method for the simultaneous analysis of twenty-six AMs including sulfonamides, tetracyclines, (fluoro)quinolones, macrolides, trimethoprim, mycophenolic acid, fluconazole, thiabendazole, and miconazole in lettuce, onion, tomato, and carrot. The method was based on a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction followed by a dispersive solid phase extraction (dSPE) clean-up in which the sorbents used were thoroughly studied in terms of analyte recoveries and minimisation of possible matrix interferences. The method was satisfactorily validated at 5 µg·kg-1, 25 µg·kg-1 and 50 µg·kg-1 in all the vegetable matrices. As regards to trueness requirements (70-130 %), they were more adequately achieved using the matrix-matched calibration approach compared to the use of deuterated analogues, with few exceptions. For optimisation tasks and multitarget quantitative analysis, an Ultra-High Performance Liquid Chromatograph coupled to a triple quadrupole mass spectrometer (UHPLC-QqQ) was used, whose sensitivity in terms of procedural limits of quantification (LOQPRO) and matrix effect at the detection were compared to the ones of a quadrupole-Orbitrap (UHPLC-qOrbitrap). LOQPRO ranged from 0.1-2.8 μg·kg-1 for UHPLC-QqQ and 1.5-90 μg·kg-1 and 1.6-70 μg·kg-1 for qOrbitrap in confirmation and discovery modes, respectively, while a higher ion-enhancement was observed when UHPLC-QqQ was employed. Twenty-five market vegetable samples from ecological and conventional agriculture were submitted to multitarget analysis and only sulfamethazine and sulfapyridine were detected in lettuce at 1.2 μg·kg-1 and 0.5 μg·kg-1, respectively. For the identification of transformation products (TPs), a data base gathering the exact mass, the isotopic profile, the fragmentation and the most possible TPs of the target analytes (using the BioTransformer 3.0 software and NORMAN database) was prepared. Brefeldin A and Netilmicin were identified and categorised using Schymanski scale at level 2b and 2a, respectively, while Isoquinolone/Quinolone and 8-hydroquinoline were tentatively identified at level 3.