title: Ionic liquid-based electromembrane extraction and its comparison with traditional organic solvent based electromembrane extraction for the determination of strychnine and brucine in human urine.
abstract: An ionic liquid-based electromembrane extraction (IL-EME) method was presented, and its performance was compared with 2-ethylnitrobenzene (ENB) based EME for the determination of strychnine and brucine in human urine. For the two methods, the fundamental extraction parameters such as supported liquid membrane, voltage, extraction time, pH values of sample solution and acceptor solution, temperature and salting-out effect were separately optimized. IL-EME provided 96- and 122-fold enrichment factors for strychnine and brucine, respectively, which were better than those obtained in EME (83- and 86-fold, respectively). The calibration curves were linear over the ranges of 20-720 μg L(-1) for strychnine and 20-640 μg L(-1) for brucine with the correlation coefficients higher than 0.9950. The repeatability of EME and IL-EME were evaluated by five parallel experiments giving the relative standard deviations of 5.12-6.98%. As the results indicated, compared with ENB based EME, the proposed IL-EME is more reliable and could provide better extraction performance for the determination of strychnine and brucine in human urine.
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, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100039, People's Republic of China.
authors.forename: Jian-Nan
authors.initials: JN
authors.lastname: Sun
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, People's Republic of China. Electronic address: chenjuan@licp.cas.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
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, People's Republic of China. Electronic address: shiyp@licp.cas.cn.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Shi
mesh_terms: D002138:Calibration; D006801:Humans; D052578:Ionic Liquids / Q000737:chemistry*; D008567:Membranes, Artificial; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry*; D013331:Strychnine / Q000031:analogs & derivatives* / Q000652:urine*; D016482:Urinalysis / Q000379:methods*
chemical_list: D052578:Ionic Liquids; D008567:Membranes, Artificial; D012997:Solvents; C083806:brucine; D013331:Strychnine
keywords: Brucine; Electromembrane extraction; Human urine; Ionic liquid; Strychnine