Ionic liquid-assisted liquid–liquid microextraction based on the solidification of floating organic droplet in sample preparation for simultaneous determination of herbicide residues in fruits

Abstract

An ionic liquid-assisted liquid–liquid microextraction based on the solidification of floating organic droplet (ILSFOD-LLME) was investigated for analysis of four herbicide residues (i.e. simazine, atrazine, propazine, and linuron) by high performance liquid chromatography. For ILSFOD-LLME, the optimal extraction conditions were 5% w/v Na2SO4, 30 μL [C4MIM][PF6]RTIL, 100 μL of 1-octanol, ultrasonication time 30 s and centrifugation at 5000 rpm for 5 min. Under the optimal conditions, linearity was obtained within the range of 0.1–1000 μg kg–1, with the correlation coefficients greater than 0.999. The high enrichment factors of the target analytes were in the range of 64.5–139.9 and low limit of detection could be obtained. A modified QuEChERS was applied for fruit sample preparation before analysis. Matrix effects were also investigated using matrix matched standards for construction of the calibration graph. The proposed method has been successfully applied for extraction and preconcentration of herbicide residues in fruit samples, and good recoveries in the range of 87.32% to 99.93% were obtained.