title: Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization.
abstract: A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH3I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 microg kg(-1). Limit of detection (LOD) of barbital was 0.2 microg kg(-1) and that of amobarbital and phenobarbital were both 0.1 microg kg(-1) (S/N > or = 3). Limit of quantification (LOQ) was 0.5 microg kg(-1) for three barbiturates (S/N > or = 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%.
authors: College of Science, China Agricultural University, Beijing 100094, China.
authors: Haixiang
authors: H
authors: Zhao
authors: Liping
authors: L
authors: Wang
authors: Yueming
authors: Y
authors: Qiu
authors: Zhiqiang
authors: Z
authors: Zhou
authors: Weike
authors: W
authors: Zhong
authors: Xiang
authors: X
authors: Li
mesh_terms: D000327:Adsorption; D000654:Amobarbital / Q000032:analysis; D000818:Animals; D001462:Barbital / Q000032:analysis; D001463:Barbiturates / Q000032:analysis*; D002138:Calibration; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004583:Electrons; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007477:Ions; D008872:Microwaves; D037742:Nanotubes, Carbon / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods*; D013552:Swine; D014465:Ultrasonics
chemical_list: D001463:Barbiturates; D007477:Ions; D037742:Nanotubes, Carbon; D001462:Barbital; D000654:Amobarbital