title: [Determination of fipronil and its metabolites in tea by solid-phase microextraction coupled with gas chromatography and gas chromatography-mass spectrometry].
abstract: An effective multi-residue method for the trace analysis of fipronil and four metabolites (fipronil-desulfinyl, fipronil-sulfide, fipronil-sulfone and fipronil-carboxamide) in tea was developed based on solid-phase microextraction coupled with gas chromatography (SPME-GC). The targets were extracted with a fused-silica fiber coated with 85 microm polyacrylate (PA). The extraction was performed in a pH 9 buffer (containing 0.1 mol/L boracic acid, 0.1 mol/L KCI and 0.1 mol/L NaOH) at 60 degrees C and under 2500 r/min for 30 min. With the concentration range of 2-10 microg/kg, the recoveries ranged from 71.2% to 109.3% and the relative standard deviations (RSDs) were lower than 10% (n = 6). The limits of detection (LODs) and limits of quantitation (LOQs) of the studied compounds ranged from 0.3 microg/kg to 1.2 microg/kg and 1.0 microg/kg to 4.0 microg/kg, respectively, with the values well below the residue limits set by Japan, European Union and China. By the proposed method, 1 positive samples of 30 tea samples were found with fipronil and fipronil-sulfone. The identification of the method was done by gas chromatography-mass spectrometry (GC-MS). The method can be applied as a monitoring tool for tea, in the investigation of food to fipronil and its metabolites.
authors.affiliation: Inspection and Quarantine Technology Center, Xiamen Entry-Exit Inspection and Quarantine Bureau, Xiamen 361026, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Dunming
authors.initials: D
authors.lastname: Xu
authors.forename: Dajie
authors.initials: D
authors.lastname: Chen
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xianghua
authors.initials: X
authors.lastname: Zheng
authors.forename: Enhua
authors.initials: E
authors.lastname: Fang
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007306:Insecticides / Q000032:analysis / Q000378:metabolism; D011720:Pyrazoles / Q000032:analysis* / Q000378:metabolism; D052617:Solid Phase Microextraction / Q000379:methods; D013662:Tea / Q000737:chemistry*
chemical_list: D007306:Insecticides; D011720:Pyrazoles; D013662:Tea; C082360:fipronil