title: Determination of multiple drugs of abuse in human urine using capillary electrophoresis with fluorescence detection.
abstract: Methods for separation and determination of multiple drugs of abuse in biological fluids using capillary electrophoresis (CE) with native fluorescence and laser-induced fluorescence (LIF) detection are described herein. Using native fluorescence, normorphine, morphine, 6-acetyl morphine (6-AM), and codeine were analyzed by CE without any derivatization procedure and detected at an excitation wavelength of 245 nm with a cut-off emission filter of 320 nm, providing a rapid and simple analysis. The detection limits were in the range of 200 ng/mL. For a highly sensitive analysis, LIF detection was also examined using a two-step precolumn derivatization procedure. In this case, drugs extracted from human urine were first subjected to an N-demethylation reaction involving the use of 1-chloroethyl chloroformate (ACE-Cl) and then derivatized using fluorescein isothiocyanate isomer I (FITC) and analyzed by CE coupled to a LIF detector. Variables affecting this derivatization: yield of demethylation reaction, FITC concentration, reaction time and temperature, were studied. The estimated instrumental detection limits of the FITC derivatives were in the range of 50-100 pg/mL, using LIF detection with excitation and emission wavelengths of 488 nm and 520 nm, respectively. The linearity, reproducibility and reliability of the methods were evaluated. In addition, a comparison of the characteristics for both native fluorescence and LIF detections was also discussed.
authors.affiliation: Department of Chemistry and Biochemistry, Clippinger Laboratories, Ohio University, Athens, OH 45701, USA.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Alnajjar
authors.forename: Jared A
authors.initials: JA
authors.lastname: Butcher
authors.forename: Bruce
authors.initials: B
authors.lastname: McCord
mesh_terms: D003061:Codeine / Q000032:analysis* / Q000652:urine; D019075:Electrophoresis, Capillary; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D006801:Humans; D009020:Morphine / Q000032:analysis* / Q000652:urine; D009022:Morphine Derivatives / Q000032:analysis* / Q000652:urine; D013050:Spectrometry, Fluorescence
chemical_list: D009022:Morphine Derivatives; D009020:Morphine; D016650:Fluorescein-5-isothiocyanate; D003061:Codeine; C010616:normorphine