title: Dynamic microwave-assisted extraction online coupled with single drop microextraction of organophosphorus pesticides in tea samples.
abstract: A new method for the determination of seven organophosphorus pesticides was developed using dynamic microwave-assisted extraction online coupled with single drop microextraction prior to gas chromatographic mass spectrometry (GC-MS). The method combines the advantages of dynamic microwave-assisted extraction and single-drop microextraction, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, tea samples were extracted with 25% ethanol aqueous solution and purified with acidic alumina at the same time, and then the analytes were concentrated into microextraction solvent. When the extraction was completed, the solvent microdrop containing the enriched analytes was retracted into the microsyringe and directly analyzed by GC-MS without any filtration or cleanup step. The method makes extraction, cleanup, separation, and enrichment to be carried out in one step. Several experimental parameters, including type of extraction solvent, type and amount of dispersant, type and volume of microextraction solvent, microwave power, extraction time, and flow rate of extraction solvent were investigated and optimized. Under optimal experimental conditions, good linearity was observed in the range of 2.00-500.00 μg kg(-1). The limits of detection and quantification were in the range of 0.4-1.7 μg kg(-1) and 1.1-5.6 μg kg(-1), respectively. The present method was applied to the analysis of tea samples, and the recoveries of analytes were in the range of 84.9-106.4% with the relative standard deviations ranging from 1.0 to 6.1%. The results showed that the present method was a rapid and feasible method for the determination of organophosphorus pesticides in tea samples.
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Lijie
authors.initials: L
authors.lastname: Wu
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Hu
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Zhanchao
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Song
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Hanqi
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China.
authors.forename: Aimin
authors.initials: A
authors.lastname: Yu
authors.affiliation: Chinese Academy of Inspection and Quarantine, Beijing, 100123, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ma
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China. Electronic address: wangziming@jlu.edu.cn.
authors.forename: Ziming
authors.initials: Z
authors.lastname: Wang
mesh_terms: D005504:Food Analysis / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D008872:Microwaves; D010575:Pesticides / Q000032:analysis*; D012997:Solvents / Q000737:chemistry; D013662:Tea / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D010575:Pesticides; D012997:Solvents; D013662:Tea; D014874:Water Pollutants, Chemical
keywords: Acidic alumina; Dynamic microwave-assisted extraction; Gas chromatographic mass spectrometry; Organophosphorus pesticides; Single drop microextraction; Tea samples