title: High-performance thin-layer chromatographic analysis of selected organophosphorous pesticide residues in tea.
abstract: The separation of 9 organophosphates (monocrotophos, quinalphos, triazophos, parathion-methyl, isofenphos-methyl, temephos, parathion, phoxim-ethyl, and chlorpyrifos) by high-performance thin-layer chromatography (HPTLC) with automated multiple development was studied. The HPTLC method was developed and validated for analysis of residues of phoxim-ethyl and chlorpyrifos in tea. The sample was extracted with acetonitrile and cleaned up by ENVI-CARB solid-phase extraction. The extract was directly applied as bands to glass-backed silica gel 60F254 HPTLC plates. The plates were developed with dichloromethane-hexane (1 + 1, v/v) in a glass twin-trough chamber. Evaluation of the developed HPTLC plates was performed densitometrically. The results indicated that the detection limits of phoxim and chlorpyrifos were 5.0 x 10(-9) and 1.0 x 10(-8) g, respectively. Recoveries of the pesticides from tea by this analytical method were 90.7-105.5%, and relative standard deviations were 7.3-13.5%. The precision and accuracy of the method were generally satisfactory for analysis of pesticide residues in tea.
authors.affiliation: International Center for Bamboo and Rattan, Beijing, People's Republic of China. yueyd@icbr.ac.cn
authors.forename: Yongde
authors.initials: Y
authors.lastname: Yue
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.forename: Feng
authors.initials: F
authors.lastname: Tang
mesh_terms: D002138:Calibration; D002855:Chromatography, Thin Layer; D003720:Densitometry; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D052616:Solid Phase Extraction; D012996:Solutions; D013662:Tea / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D009943:Organophosphorus Compounds; D010573:Pesticide Residues; D012996:Solutions; D013662:Tea