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Zeolite/Polymer‐Modification of a Mercury Electrode. Effects on the Cu 2+ Interference in the Stripping Determination of Zn 2+
Author(s) -
Mogensen Lene,
Kryger Lars
Publication year - 1998
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(199812)10:18<1285::aid-elan1285>3.0.co;2-v
Subject(s) - zeolite , stripping (fiber) , mercury (programming language) , electrode , anodic stripping voltammetry , analytical chemistry (journal) , materials science , chemistry , polymer , ion exchange , membrane , inorganic chemistry , ion , catalysis , electrochemistry , chromatography , composite material , organic chemistry , computer science , programming language , biochemistry
The present study was carried out in order to investigate whether zeolite 13X (aperture 7.4 A˚) modification of a mercury electrode could provide discrimination against the interference from Cu 2+ in the stripping determination of Zn 2+ (utilizing the zeolite ion exchange capability, and the possibility for small differences in size and shape of hydrated Zn 2+ and Cu 2+ and hence the differences in zeolite affinity to these species). For this purpose a chemically modified electrode (CME) was constructed from a glassy carbon electrode, which was first coated with a zeolite 10X containing polymer matrix then subjected to mercury plating. The analytical characteristics of the CME were subsequently compared with those of a conventional thin mercury film electrode (TMFE). The comparison, which was based on analogous stripping experiments carried out using first the TMFE, then the CME, showed that stripping signals for Zn 2+ as well as Cu 2+ were obtained with both electrodes. However, the intermetallic compound interference observed for the CME Zn‐response was much less pronounced than that encountered for the TMFE Zn‐response, thus indicating that the zeolite modification provided a marked discrimination towards deposition of Cu 2+ . Subsequent standard addition experiments with 60 s depositions at −1200 mV revealed that the Zn‐stripping signal obtained with the CME was linear for 0–3.5 μM Zn 2+ in the presence of 10 μM Cu 2+ .