ionic liquid-based air-assisted liquid–liquid microextraction for the extraction and preconcentration of aryloxyphenoxypropionate herbicides from aqueous and vegetable samples followed by hplc-dad

An efficient, reliable, sensitive, rapid, and environmentally friendly analytical method has been developed for the extraction and determination of aryloxyphenoxypropionate herbicides in aqueous and vegetable samples using ionic liquid-based air-assisted liquid–liquid microextraction coupled with high-performance liquid chromatography-diode array detector. in this method, a few microliters of 1-hexyl-3-methylimidazolium hexafluorophosphate (as an extractant) is transferred into the aqueous solution containing the analytes. fine droplets of the extractant are formed by repeated aspirating and dispersing of the mixture via a syringe needle. during this period, the analytes are extracted into the ionic liquid and then collected at the bottom of the tube after centrifugation. under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.16 and 0.31 and 0.52 and 0.99 ng ml−1, respectively. extraction recoveries and enrichment factors were in the ranges of 76–83 % and 380–415, respectively. the relative standard deviations for the extraction of 1.5 ng ml−1 of each analyte were less than 5.2 % for intra-day (n = 6) and inter-day (n = 4) precisions. finally, different aqueous and vegetable samples were successfully analyzed using the proposed method, and two analytes were determined in some of them at ng ml−1 level.