title: Applicability of cloud point extraction coupled with microwave-assisted back-extraction to the determination of organophosphorous pesticides in human urine by gas chromatography with flame photometry detection.
abstract: A procedure for the determination of organophosphorous pesticides (OPPs) - phorate, diazinon, parathion-methyl, fenthion and quinalphos - in human urine was developed using the cloud point extraction of nonionic surfactant (Triton X-114) coupled with microwave-assisted back-extraction prior to gas chromatography with flame photometry detection (GC-FPD) analysis. The upper organic solution obtained from back-extraction was centrifugated simply for further cleanup for the sake of automatic injection. A preconcentration factor of 50 was obtained for these five OPPs extracted from only 10 mL of a sample. The limits of detection (LODs) were 0.07 ng mL(-1) for phorate, fenthion and quinalphos, 0.04 ng mL(-1) for diazinon and 0.08 ng mL(-1) for parathion-methyl. The limits of quantification (LOQs) were 0.21, 0.12, 0.24, 0.21 and 0.21 ng mL(-1), respectively. Accuracy of the method was evaluated by bias, which ranged from +6.85 to -14.68%. Precision was also good; the relative standard deviations (R.S.D.s) were less than 9%. The method showed to be potential for biological monitoring.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Beijing 100094, China.
authors.forename: Guifang
authors.initials: G
authors.lastname: Jia
authors.forename: Chunguang
authors.initials: C
authors.lastname: Lv
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhu
authors.forename: Jing
authors.initials: J
authors.lastname: Qiu
authors.forename: Xinquan
authors.initials: X
authors.lastname: Wang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D002138:Calibration; D002498:Centrifugation; D002849:Chromatography, Gas; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008872:Microwaves; D010755:Organophosphates / Q000652:urine*; D010575:Pesticides / Q000652:urine*; D010783:Photometry; D015203:Reproducibility of Results; D013048:Specimen Handling; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature
chemical_list: D007202:Indicators and Reagents; D010755:Organophosphates; D010575:Pesticides; D013501:Surface-Active Agents