Identification of adjuvants in plant protection products applying a suspect screening workflow based on orthogonal techniques

In this study, the identification of adjuvants (surfactants and solvents) in quizalofop-p-ethyl plant protection products (PPPs) was carried out by applying nuclear magnetic resonance (NMR), ultra-high-performance liquid chromatography (UHPLC) and gas chromatography (GC), both coupled to high-resolution mass spectrometry (HRMS), and using a suspect analysis approach. NMR provided a rapid and global overview of the composition of the studied samples and supported the tentative identification of the glycol ether family, commonly employed as surfactants, and 2-ethyl-1-butanol. UHPLC-HRMS was used for characterization of the glycol polymer surfactants, while GC-HRMS was used to obtain information about volatile organic compounds (benzene or naphthalene derivates) present in the PPPs. A total of nine adjuvants were characterized in the tested PPPs, belonging to naphthalene, benzene, sulphate and fatty acid esters of glycerol families. In addition, the estimation of compound concentrations was carried out using GC(LC)-HRMS, and finally, these concentration levels were related to their toxicity values.