title: Optimization of the separation and on-line sample concentration of phenethylamine designer drugs with capillary electrophoresis-fluorescence detection.
abstract: Five 2C-series of phenethylamine designer drugs, including 2,5-dimethoxy-4-ethylthio-phenethylamine (2C-T-2), 2,5-dimethoxy-4-(n)-propylthiophenethylamine (2C-T-7), 4-chloro-2,5-dimethoxyphenethylamine (2C-C), 4-bromo-2,5-dimethoxy-phenethylamine (2C-B), 2,5-dimethoxy-4-iodo-phenethylamine (2C-I), were synthesized and standard GC/MS and fluorescence spectra are reported for them. A mixture of the five drugs was separated and detected by means of capillary electrophoresis (CE) with native fluorescence and light emitting diode (LED)-induced fluorescence (LIF) detection, respectively, for comparison. In the former case, exciting at a wavelength of 300 nm from a Xe lamp was used. The detection limits were found to be only in the range of approximately 10(-4) M by the micellar electrokinetic chromatography (MEKC) mode but were improved to approximately 10(-7) M when the sweeping-MEKC mode was used. For a highly sensitive analysis, LED-induced fluorescence detection was examined by derivatizing the compounds with a fluorescent dye, fluorescein isothiocyanate isomer I (FITC). A blue-LED (approximately 2 mW) was used as the fluorescence excitation source. The detection limits were improved to approximately 10(-7) and approximately 10(-8) M, respectively, when the MEKC and stacking-MEKC modes were applied. A mimic urine sample was obtained by spiking urine from a volunteer with the five standards, and after liquid-liquid extraction, the sample was examined by means of the MEKC-LIF mode. The extraction procedures used for the urine sample and the CE conditions for the separation were optimized.
authors.affiliation: Department of Chemistry, National Taiwan Normal University, 88 Sec. 4, Tingchow Road, Taipei, Taiwan.
authors.forename: Chung-Chen
authors.initials: CC
authors.lastname: Tsai
authors.forename: Ju-Tsung
authors.initials: JT
authors.lastname: Liu
authors.forename: You-Ren
authors.initials: YR
authors.lastname: Shu
authors.forename: Po-Han
authors.initials: PH
authors.lastname: Chan
authors.forename: Cheng-Huang
authors.initials: CH
authors.lastname: Lin
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods; D015198:Designer Drugs / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D010627:Phenethylamines / Q000302:isolation & purification* / Q000652:urine; D013050:Spectrometry, Fluorescence
chemical_list: D015198:Designer Drugs; D010627:Phenethylamines