Assessment of Co-Formulants in Marketed Plant Protection Products by LC-Q-Orbitrap-MS: Application of a Hybrid Data Treatment Strategy Combining Suspect Screening and Unknown Analysis.

The aim of this study was the determination of co-formulants in 15 different chlorantraniliprole- and difenoconazole-based plant protection products (PPPs) belonging to different formulations. Samples were analyzed by ultrahigh-performance liquid chromatography coupled to Q-Orbitrap high-resolution mass accuracy spectrometry (UHPLC-Q-Orbitrap-MS), operating in full-scan MS and data-dependent acquisition (ddMS2) modes. A total of 78 co-formulants were tentatively identified by a combination of suspect screening and unknown analysis. Nine of them were later confirmed by analytical standards. Finally, the analytical method was successfully validated and co-formulants were quantified. Linear alkyl ethoxylates (LAS) were the most common type of co-formulant, followed by sodium alkylbenzene sulfonates. Moreover, sodium dodecyl benzene sulfonate had the highest concentration of any co-formulant (up to 32.33 g/L). In all, an innovative identification of co-formulants in a large number of PPPs is presented, which will give room for future studies delving into the composition of PPPs or determining these co-formulants in environmental or agricultural samples.

A laboratory study on dissipation and risk assessment of the proinsecticide thiocyclam and its metabolite nereistoxin in tomato using liquid chromatography high resolution mass spectrometry.

Reduced pesticides use, alongside increased organic farming, has created a need for new biological products, such as thiocyclam, to control pests. Thiocyclam has scarcely been studied, making the study of its degradation in fruits and vegetables, such as tomatoes, an urgent requirement. To monitor thiocyclam metabolites in tomato, dissipation studies were carried out using a liquid chromatography-Orbitrap mass spectrometry (UHPLC-Orbitrap MS) method for 60-days after foliar application. Thiocyclam was not persistent (DT50 < 15 days), but nereistoxin - its primary metabolite - remained present in the tomatoes for >60 days. Four nereistoxin metabolites, detected at low concentrations (<100 µg/kg), were also monitored. This is the first time a study has provided dissipation patterns for thiocyclam and nereistoxin. The results obtained suggest revising the legislation concerning these compounds is required. Toxicological studies must also be carried out because there is no toxicity data currently for thiocyclam or nereistoxin.