Stereoselective separation of sulfoxaflor by electrokinetic chromatography and applications to stability and ecotoxicological studies

•First separation of the four sulfoxaflor stereoisomers by Capillary Electrophoresis.•Stability and ecotoxicological studies used real and not nominal concentrations.•Stability of racemic sulfoxaflor and its stereoisomers varies with a similar pattern.•Sulfoxaflor can be considered as toxic and very toxic to aquatic ecosystems.•Sulfoxaflor shows same or higher toxicity than predecessor insecticide imidacloprid. An Electrokinetic Chromatography method was developed for the stereoselective analysis of sulfoxaflor, a novel sulfoximine agrochemical with two chiral centers. A screening with fourteen negatively charged CDs was performed and Succinyl-β-CD (Succ-β-CD) was selected. A 15 mM concentration of this CD in a 100 mM borate buffer (pH 9.0), using an applied voltage of 20 kV and a temperature of 15 °C made possible the baseline separation of the four stereoisomers of sulfoxaflor in 13.8 min. The evaluation of the linearity, accuracy, precision, LODs and LOQs of the method developed showed its performance to be applied to the analysis of commercial agrochemical formulations, the evaluation of the stability of sulfoxaflor stereoisomers under biotic and abiotic conditions, and to predict, for the first time, sulfoxaflor toxicity (using real concentrations instead of nominal concentrations), on two non-target aquatic organisms, the freshwater plant, Spirodela polyrhiza, and the marine bacterium, Vibrio fischeri.