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Amperometric Detection of Biologically Significant Sulfur‐Containing Compounds at Bi(V)‐Doped PbO 2 Film Electrodes
Author(s) -
Popović Nataša Đ,
Johnson Dennis C.
Publication year - 1999
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/(sici)1521-4109(199909)11:13<934::aid-elan934>3.0.co;2-f
Subject(s) - amperometry , chemistry , thioether , cyclic voltammetry , sulfoxide , sulfur , electrode , detection limit , cationic polymerization , inorganic chemistry , electrochemistry , chromatography , organic chemistry
Electrocatalytic oxidation of sulfur‐containing amino acids and peptides at Bi(V)‐doped β‐PbO 2 film electrodes (Bi‐PbO 2 ) was investigated in acidic media and tested for amperometric detection of representatives of these compounds following their separation as cationic species in a chromatographic column that exhibits both cation‐exchange and reversed‐phase properties. The Bi‐PbO 2 film electrodes permit detection with similar sensitivities for compounds that contain sulfhydryl, disulfide, thioether, and sulfoxide moieties. More specifically, detection limits at the pmol level were obtained for all analytes of interest. The Bi‐PbO 2 electrodes were characterized by cyclic voltammetry, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). For the acidic media used in this study, only the nonsulfur containing amino acids tryptophane and tyrosine produced an anodic response; however, this occurred only at concentrations >50 μM. The linear dynamic range of response for methionine is demonstrated to be a sensitive function of applied potential. This observation is concluded to be consistent with a response mechanism by which a prerequisite is the anodic discharge of H 2 O to produce adsorbed OH radicals that are the immediate source of O‐atoms transferred to the oxidation products.