Journal Article

A Rapid Reusable Fiber Optic Biosensor for Detecting Cocaine Metabolites in Urine

Nidhi Nath, Mohyee Eldefrawi, Jeremy Wright, David Darwin and Marilyn Huestis

in Journal of Analytical Toxicology

Volume 23, issue 6, pages 460-467
Published in print October 1999 | ISSN: 0146-4760
Published online October 1999 | e-ISSN: 1945-2403 | DOI:
A Rapid Reusable Fiber Optic Biosensor for Detecting Cocaine Metabolites in Urine

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Analyte 2000, a four-channel fiber optic biosensor (FOB), was used for analysis of cocaine and its metabolites (COC) in human urine using a competitive fluorescence immunoassay. Binding of antibenzoylecgonine monoclonal antibody (mAb) to the casein-benzoylecgonine Ag-coated, tapered optical fibers was inhibited by COC. Bound mAb, which inversely correlated with COC concentration, was quantitated by fluorescence produced by evanescent excitation of bound cyanine dye-tagged antimouse antibody (CY5-Ab). The effective concentration range of benzoylecgonine (BE) for inhibiting the fluorescent signals was 0.75–50 ng/mL, with IC50 of 9.0 ng/mL. This FOB had similar affinities for BE, cocaine, and cocaethylene, but very low affinities for ecgonine and ecgonine methyl ester. A sensitivity of 100% and a specificity of 96% were achieved when 54 human urine specimens were analyzed by FOB (cutoff, 300 ng/mL COC) and GC-MS (cutoff, 150 ng/ml. BE). All results were in agreement except for one positive FOB result with a GC-MS BE concentration of 148 ng/mL. In addition, regeneration and reuse of the fiber for multiple analyses were performed successfully with no carryover from specimens containing high COC concentrations to specimens containing low COC concentrations.

Journal Article.  0 words. 

Subjects: Medical Toxicology ; Toxicology (Non-medical)

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