Analysis of fluorescein isothiocyanate derivatized amphetamine and analogs in human urine by capillary electrophoresis in chip-based and fused-silica capillary instrumentation.
Amines can easily be derivatized with fluorescein isothiocyanate isomer I (FITC) and analyzed by capillary electrophoresis (CE) using alkaline buffers with or without dodecyl sulfate micelles. This paper reports the CE analysis of FITC-derivatized amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine and beta-phenylethylamine in human urine using chip-based and fused-silica capillary instrumentation with laser-induced fluorescence detection. Data obtained via direct labeling of fortified urine are compared to those generated after FITC labeling of urinary extracts that were prepared by solid-phase extraction using a copolymer phase. For a urine volume of 5 mL with a "spiked amine": FITC ratio of 1:250, the latter approach was found to provide a sensitivity that is relevant for toxicological drug screening and confirmation (about 200 ng/mL urine). With direct labeling of 10 microL urine that was alkalinized and diluted for derivatization, the limit of identification was determined to be about 10 microg/mL, a value that is too high for practical purposes. Compared to fused-silica capillaries, electrophoresis in microstructures is shown to provide faster separations and higher efficiencies without loss of accuracy and precision.
Ramseier
A
A
Department of Clinical Pharmacology, University of Bern, Switzerland.
von Heeren
F
F
Thormann
W
W
D000662:Amphetamines / Q000652:urine*; D000697:Central Nervous System Stimulants / Q000652:urine*; D020374:Chromatography, Micellar Electrokinetic Capillary; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006801:Humans; D015813:Substance Abuse Detection / Q000379:methods*
D000662:Amphetamines; D000697:Central Nervous System Stimulants; D005456:Fluorescent Dyes; D016650:Fluorescein-5-isothiocyanate