title: Analysis of cocaine, benzoylecgonine, ecgonine methyl ester, ethylcocaine and norcocaine in human urine using HPLC with post-column ion-pair extraction and fluorescence detection.
abstract: The measurement of cocaine and its major metabolites has been achieved by an HPLC method that compensates for their different solubilities and detection properties. Although ecgonine methyl ester is a major metabolite it is generally not measured by HPLC because it is poorly detectable by UV, and its water solubility makes recovery from urine difficult. Using modified solid-phase extraction procedures recoveries of 85% for ecgonine methyl ester, 97% for cocaine, 106% for benzoylecgonine and 80% for ethylcocaine have been obtained from urine. Increased chromatographic retention and detection sensitivity has been obtained by formation of the t-butyldimethylsilyl derivative of ecgonine methyl ester which was found to be stable in the HPLC mobile phase for at least 1 week. Alkylation of norcocaine and benzoylecgonine has improved their detection sensitivity and also chromatographic resolution. All calibrations were linear over the range 200-1000 ng ml-1 in urine with correlation coefficients > 0.99.
authors.affiliation: School of Pharmacy and Pharmacology, University of Bath, Claverton Down, UK.
authors.forename: I M
authors.initials: IM
authors.lastname: Roy
authors.forename: T M
authors.initials: TM
authors.lastname: Jefferies
authors.forename: M D
authors.initials: MD
authors.lastname: Threadgill
authors.forename: G H
authors.initials: GH
authors.lastname: Dewar
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000031:analogs & derivatives* / Q000652:urine*; D006801:Humans; D014179:Neurotransmitter Uptake Inhibitors / Q000652:urine; D013050:Spectrometry, Fluorescence
chemical_list: D014179:Neurotransmitter Uptake Inhibitors; C008671:norcocaine; C005618:benzoylecgonine; C066444:cocaethylene; D003042:Cocaine; C034524:ecgonine methyl ester