title: Effective extraction method for determination of neonicotinoid residues in tea.
abstract: Sample preparation using an absorbent for removal of polyphenols and a solid-phase extraction (SPE) cartridge for cleanup followed by high-performance liquid chromatography (HPLC) has been investigated for the simultaneous determination of eight neonicotinoid insecticides (dinotefuran, nitenpyram, thiamethoxam, imidacloprid, clothianidin, imidaclothiz, acetamiprid, and thiacloprid). After tea samples were soaked with water and extracted with acetonitrile, sample extracts were treated with an appropriate amount of polyvinylpolypyrrolidone (PVPP) to effectively remove polyphenols. The treated extract was cleaned up with a Carb-PSA cartridge. Neonicotinoid insecticides were eluted with acetonitrile from the cartridge and dried. The extract was redissolved with methanol/water (1:9, v/v) and analyzed by conventional HPLC coupled with an ultraviolet detector. The recoveries of eight neonicotinoid insecticides in tea samples were 71.4-106.6% at 0.1-1.0 mg kg(-1) spiked levels. Relative standard deviations were <10% for all of the recovery tests. The established method was simple, effective, and accurate and could be used for monitoring neonicotinoid insecticides in tea.
authors.affiliation: Key Laboratory of Tea Biochemistry and Biotechnology, Ministry of Agriculture and Ministry of Education, Anhui Agricultural University , Hefei 230036, People's Republic of China.
authors.forename: Ru-Yan
authors.initials: RY
authors.lastname: Hou
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Jiao
authors.forename: Xiao-San
authors.initials: XS
authors.lastname: Qian
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiao
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Wan
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D007306:Insecticides / Q000032:analysis / Q000302:isolation & purification*; D010573:Pesticide Residues / Q000032:analysis / Q000302:isolation & purification*; D052616:Solid Phase Extraction / Q000379:methods*; D013662:Tea / Q000737:chemistry*
chemical_list: D007306:Insecticides; D010573:Pesticide Residues; D013662:Tea