Degradation of co-formulants and metabolites from plant protection products in courgette and tangerine using LC-HRMS: Laboratory tests

Abstract

Plant protection products contain co-formulants that could end up in vegetables, and they can generate transformation products that can be more toxic than their original molecule, which are a potential risk to food safety. Therefore, this study evaluated the dissipation of two co-formulants, dodecylbenzenesulfonic acid and 1-ethyl-2-pyrrolidone, in courgette and tangerine samples to determine possible harmful metabolites under laboratory conditions. The analyses of these substances were performed by liquid chromatography coupled to quadrupole-Orbitrap high-resolution mass spectrometry (LC-Q-Orbitrap-HRMS). For the degradation of both compounds, a single-phase kinetic model was fitted, with R2 values greater than 0.99. In courgette and tangerine, half-lives (DT50) for dodecylbenzene sulfonic acid were 1.83 and 1.42 days, while DT50 was 6.26 and 5.04 days for 1-ethyl-2-pyrrolidone, respectively. Three metabolites of dodecylbenzenesulfonic acid and five metabolites of 1-ethyl-2-pyrrolidone were found in courgette, while the same metabolites were detected in tangerine samples, except benzoic acid and 4-aminobutanoic acid. These metabolites were identified for the first time from these compounds except for benzoic acid, observing that 5-hydroxy-N-ethylpyrrolidone was the most concentrated metabolite in tangerine 14 days after application, reaching a maximum concentration of 149 µg/kg. Furthermore, some of the detected metabolites possessed a value of LD50 lower than their original molecules. In consequence, such metabolites, derived from these co-formulants, should be controlled to prevent negative health effects, and ensure food safety.