title: Amperometric detection of morphine at a Prussian blue-modified indium tin oxide electrode.
abstract: In this work, the electrocatalytic oxidation of morphine (MO) at an optically transparent indium tin oxide (ITO) electrode modified by an electrodeposited Prussian blue (PB) thin film is first demonstrated, and the amperometric detection of MO was then investigated. Experimental results showed that the thin film on the ITO surface, confined to the PB/Berlin green (BG) redox pair, can serve as an excellent mediator which facilitates electron transfer and considerably lowers the overpotential required, as compared to a bare ITO electrode. Thus, PB can be regarded as a promising artificial peroxidase for MO. The rate of such an electrocatalytic reaction is pH dependent with the highest value at pH 5. By potential-step excitation from 0.55 to 0.70 V, a linear calibration curve, displaying the relationship between steady-state currents and MO concentrations (ranging from 0.09 to 1.0 mM), was obtained. The detection sensitivity is about 16.8 microA/cm2 mM. Most importantly, the method described herein can readily discriminate MO analogs lacking the phenolic -OH group, such as codeine, and can thus benefit the specific recognition of MO.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Room 110A, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan. kcho@ntu.edu.tw
authors.forename: Kuo-Chuan
authors.initials: KC
authors.lastname: Ho
authors.forename: Chia-Yi
authors.initials: CY
authors.lastname: Chen
authors.forename: Huan-Cheng
authors.initials: HC
authors.lastname: Hsu
authors.forename: Lin-Chi
authors.initials: LC
authors.lastname: Chen
authors.forename: Shu-Chu
authors.initials: SC
authors.lastname: Shiesh
authors.forename: Xi-Zhang
authors.initials: XZ
authors.lastname: Lin
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003061:Codeine / Q000032:analysis / Q000737:chemistry; D045424:Complex Mixtures / Q000032:analysis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005295:Ferrocyanides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009020:Morphine / Q000032:analysis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D011540:Prussian Blue Reaction / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D045424:Complex Mixtures; D005295:Ferrocyanides; D017971:Tin Compounds; C109984:indium tin oxide; D009020:Morphine; C000170:ferric ferrocyanide; D003061:Codeine