title: Application of SiO(2) hollow fibers for sorptive microextraction and gas chromatography-mass spectrometry determination of organochlorine pesticides in herbal matrices.
abstract: A method involving simultaneous extraction and sample clean-up procedure: hollow fiber sorptive microextraction, coupled with gas chromatography-mass spectrometric detection for quantification of seven organochlorine pesticides in Radix et Rhizoma Rhei is described. SiO(2) hollow fiber with porous structure was synthesized for the first time. The internal diameter of SiO(2) hollow fiber is 380 microm and average wall thickness is 100 microm. Aggregated SiO(2) particles deposited on the surface of the hollow fiber in a regular array lead to porous structure. SiO(2) hollow fiber was applied to the determination of organochlorine pesticides in Radix et Rhizoma Rhei to avoid sample clean-up and minimize the matrix effects. Extraction solvent, extraction temperature and equilibration time were optimized. Fiber to fiber repeatability over the concentration ranges were less than 10%. Recoveries were satisfactory (between 63% and 115%) for most of organochlorine pesticides at spiking levels. Furthermore, the proposed method was also applied to determine seven organochlorine pesticides in 43 commercial Radix et Rhizoma Rhei samples, in which the selected pesticides were found in eight samples. The results have been further confirmed by solvent extraction methods according to China Pharmacopoeia (2005).
authors.affiliation: Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Hong-Fei
authors.initials: HF
authors.lastname: Zhang
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Shi
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D012822:Silicon Dioxide