title: Determination of four heterocyclic insecticides by ionic liquid dispersive liquid-liquid microextraction in water samples.
abstract: A novel microextraction method termed ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) combining high-performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of insecticides in water samples. Four heterocyclic insecticides (fipronil, chlorfenapyr, buprofezin, and hexythiazox) were selected as the model compounds for validating this new method. This technique combines extraction and concentration of the analytes into one step, and the ionic liquid was used instead of a volatile organic solvent as the extraction solvent. Several important parameters influencing the IL-DLLME extraction efficiency such as the volume of extraction solvent, the type and volume of disperser solvent, extraction time, centrifugation time, salt effect as well as acid addition were investigated. Under the optimized conditions, good enrichment factors (209-276) and accepted recoveries (79-110%) were obtained for the extraction of the target analytes in water samples. The calibration curves were linear with correlation coefficient ranged from 0.9947 to 0.9973 in the concentration level of 2-100 microg/L, and the relative standard deviations (RSDs, n=5) were 4.5-10.7%. The limits of detection for the four insecticides were 0.53-1.28 microg/L at a signal-to-noise ratio (S/N) of 3.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing 100094, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Ercheng
authors.initials: E
authors.lastname: Zhao
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhu
authors.forename: Haixiang
authors.initials: H
authors.lastname: Gao
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D002138:Calibration; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000032:analysis*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D006571:Heterocyclic Compounds; D007306:Insecticides; D012997:Solvents; D014867:Water; D012965:Sodium Chloride