Simultaneous determination of six novel acetolactate synthase inhibitor herbicide residues in oil crops based on ultrasound assisted extraction liquid chromatography-tandem mass spectrometry

Abstract

Ultrasound-assisted extraction coupled with liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) was used to develop a trace multi-residue detection method for six novel acetolactate synthase (ALS) inhibitor herbicide residues (mesosulfuron-methyl, halosulfuron-methyl, bispyribac-sodium, pyriminobac-methyl, orthosulfamuron, and ethoxysulfuron) in oil crops. In this study, the recoveries of the six herbicides based on ultrasound-assisted and QuEChERS extraction methods were compared, and five adsorbent materials (C18, PSA, GCB, Florisil, and EMR) were optimized based on their purification and adsorption capacities. The results showed that the ultrasound-assisted extractions gave recoveries greater than 90% for the six compounds. Furthermore, EMR showed little adsorption for the six compounds and a reduced matrix effect by effective removal of the oil lipids. The six herbicide residues had good linearities in the concentrations ranging from 0.05 to 500.0 μg/L, and the correlation coefficients were greater than 0.9984. The limits of detection and limits of quantification for this method were 0.08-0.8 μg/kg and 0.25-2.5 μg/kg, respectively. The recoveries of the six pesticides at three spiked levels in four matrices (rapeseed, soybean, peanut, and sunflower seed) ranged from 70.7% to 103.8%, with relative standard deviations of 0.8%-9.2%. This method was successfully applied to the simultaneous determination of six ALS inhibitor herbicide residues in oil crops.