title: Limit for qualitative detection of benzoylecgonine in urine using EMIT reagents and the Hitachi 705 automatic analyzer.
abstract: The limit of detection for the cocaine metabolite (hydrolysis product), benzoylecgonine, using Syva EMIT reagents and the Hitachi 705 automatic analyzer has been found to be 10 ng/mL at the 99% confidence level. For this determination 30 controls were prepared from a single urine pool known to be negative for cocaine metabolite. Urine samples of 90 patients were found to be drug-free when analyzed by selected ion monitoring gas chromatography/mass spectrometry for ecgonine methyl ester and benzoylecgonine at sensitivities of less than 0.4 ng/mL and 1.3 ng/mL, respectively. To test matrix effects on the limit of detection, these samples were screened with the Hitachi 705. Results for eight of the known negative samples fell above the 10-ng/mL limit of detection while only one presumptive positive resulted at an arbitrary 20-ng/mL cutoff. Detection limits were also determined using 20 different negative patients' urine samples fortified with benzoylecgonine. At the 99% confidence level using EMIT d.a.u. and 705 reagents the detection limits were found to be 44 ng/mL and 35 ng/mL, respectively. It was found that 62% of patients' samples positive for benzoylecgonine fell below the 300-ng/mL cutoff and above a cutoff at 50 ng/mL.
authors.affiliation: Toxicology Testing Service, Inc., Miami, Florida 33166.
authors.forename: T D
authors.initials: TD
authors.lastname: Hall
authors.forename: I
authors.initials: I
authors.lastname: Sanchez
authors.forename: L
authors.initials: L
authors.lastname: Dunlap
authors.forename: J
authors.initials: J
authors.lastname: de Kanel
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives* / Q000652:urine; D005069:Evaluation Studies as Topic; D006801:Humans; D007124:Immunoenzyme Techniques / Q000295:instrumentation*; D007202:Indicators and Reagents
chemical_list: D007202:Indicators and Reagents; C005618:benzoylecgonine; D003042:Cocaine