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Calibration‐Free Determination of Copper, Zinc, Cadmium and Lead in Tap Water Using Coulometric Stripping Potentiometry
Author(s) -
Sahlin Eskil,
Jagner Daniel
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(199807)10:8<532::aid-elan532>3.0.co;2-j
Subject(s) - chemistry , coulometry , zinc , tap water , cadmium , mercury (programming language) , copper , stripping (fiber) , stoichiometry , analytical chemistry (journal) , inorganic chemistry , electrochemistry , chromatography , materials science , electrode , organic chemistry , composite material , environmental engineering , computer science , engineering , programming language
Coulometric stripping potentiometry has been used to achieve calibration‐free determinations of Cu(II), Zn(II), Cd(II) and Pb(II) in tap water samples. With the coulometric approach, interference from the formation of Cu‐Zn intermetallic compounds (CuZn x ) on the quantification of Zn(II) was circumvented and the average stoichiometry of CuZn x could be determined. For Zn to Cu concentration ratios below 1, CuZn is quantitatively formed. At higher ratios amalgamated Zn coexists with CuZn, CuZn 2 and CuZn 3 . Both mercury soluble and mercury insoluble CuZn x exist. The former dissociates, with a half time of the order of one second, at potentials between the oxidation potentials for amalgamated Zn and that for CuZn x , while formation of the latter is irreversible. Due to interference from surface active groups on the glassy carbon surface, used as a substrate for the mercury film, determination of Zn(II) was not possible at Zn to Cu concentration ratios below approximately 0.1.