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Direct Electrocatalytic Oxidation of Cysteine and Cystine Based on Nafion/Lead Oxide‐Manganese Oxide Combined Catalyst
Author(s) -
Sudhakara Prasad Kariate,
Muthuraman Govindan,
Zen JyhMyng
Publication year - 2008
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200704133
Subject(s) - nafion , cystine , catalysis , chemistry , inorganic chemistry , oxide , hydroquinone , cysteine , detection limit , electrochemistry , redox , electrode , organic chemistry , chromatography , enzyme
This article reports direct electrocatalytic oxidation of cysteine (CySH) and cystine (CyS‐SCy) at an inexpensive Nafion/lead oxide‐manganese oxide combined catalyst in physiological pH. The synthesized lead oxide‐manganese oxide material is simply mixed with Nafion in the form of cast solution and modified on a disposable screen‐printed carbon electrode (designated as SPE/Nf‐PMO) for biosensing application. Electrochemical study with a standard redox couple of quinone/hydroquinone demonstrates an enhanced current response at the combined catalyst compared to its individual component. Surface characterization further provides information regarding the structural morphology of the catalyst to its catalytic performance. Direct electrocatalytic oxidation signals are observed at +0.75 and +1.20 V vs. Ag/AgCl for cysteine and cystine, respectively, at the SPE/Nf‐PMO. To extend the applicability, we further apply the proposed system for the detection of cysteine and cystine by flow injection analysis (FIA). Under optimized conditions, the detection limit ( S / N =3) is 0.43 μM and 0.33 μM for cysteine and cystine, respectively.