title: Determination of codeine in urine and drug formulations using a clay-modified screen-printed carbon electrode.
abstract: Both flow-injection analysis and square-wave stripping voltammetry were evaluated for the determination of codeine in pharmaceutical formulations using a nontronite clay-modified screen-printed carbon electrode. Compared with a bare screen-printed carbon electrode, the nontronite clay-modified screen-printed carbon electrode exhibited a marked enhancement of the current response of codeine. A linear calibration plot was obtained over the 2.5-45 microM range (correlation coefficient=0.999) in pH 6.0 phosphate buffer solution with a detection limit of 20 nM (S/N=3) by square-wave voltammetry (SWV). While, in flow-injection analysis, the linearity was over 5-120 ng range with a detection limit of 1 ng in 20 microl loop. The nontronite clay-modified screen-printed carbon electrode can be either disposable or reused since the renewal gave a good reproducible surface. Quantitative analysis was performed by the standard addition method for codeine content in both urine and commercially available drugs.
authors.affiliation: Department of Applied Cosmetology, Hung-Kuang Institute of Technology, 34 Chung-Chie Rd. Sha-Lu, 433, Taichung, Taiwan, ROC.
authors.forename: Y
authors.initials: Y
authors.lastname: Shih
authors.forename: J-M
authors.initials: JM
authors.lastname: Zen
authors.forename: H-H
authors.initials: HH
authors.lastname: Yang
mesh_terms: D000328:Adult; D000538:Aluminum Silicates; D002244:Carbon; D000077215:Clay; D003061:Codeine / Q000032:analysis* / Q000652:urine; D004563:Electrochemistry; D004566:Electrodes; D005260:Female; D017022:Flow Injection Analysis; D006801:Humans; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013607:Tablets / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D004364:Pharmaceutical Preparations; D013607:Tablets; D002244:Carbon; D000077215:Clay; D003061:Codeine