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A study of the stripping voltammetric behavior of selected metal chelates and its application to automated analysis of river waters
Author(s) -
Maxwell Tracy J.,
Franklin Smyth W.
Publication year - 1996
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.1140080817
Subject(s) - chemistry , chelation , dithiocarbamate , detection limit , supporting electrolyte , adsorption , ammonium , nuclear chemistry , chloride , chelating resin , inorganic chemistry , electrolyte , metal , chromatography , metal ions in aqueous solution , organic chemistry , electrode
The ASV and AdSV behavior of Zn 2+ , Cd 2+ , Pb 2+ , Cu 2+ , Ni 2+ and Sn 4+ in the presence of selected complexing/chelating agents has been studied. The presence of 2,5‐dimercapto‐l,3,4‐thiadiazole(I) lowers the limit of detection (LOD) for the ASV determination of Zn 2+ , Cd 2+ and Pb 2+ in 5 × 10 −3 mol dm −3 LiCl supporting electrolyte with a deposition time of 120s to 0.82, 0.17 and 0.34 ppb, respectively, due to participation of the adsorbed complexing agent in the overall process. Similarly, Cd 2+ can be determined in the presence of benzimidazole sulfoxides (II) and (III) by ASV in Britton‐Robinson (BR) buffer pH9 with 120s deposition with lower LODs of 0.12 and 0.06 ppb. respectively. AdSV can also be used to determine Cd 2+ with (II), (III) and ammonium pyrrolidine dithiocarbamate (IV) with LODs of 0.70, 0.64 and 0.20 ppb, respectively and with Zn 2+ having an AdSV LOD of 1.09 ppb using adsorption of its chelate with (IV) at −900mV for 60 s in a supporting electrolyte of 5 × 10 −3 moldm −3 LiCI. Participation of the adsorbed complexing agent in the ASV process is also observed for Sn 4+ and Cu 2+ in an oxalate/ammonium chloride/HCl buffer with lowered LODs of 0.51 ppb and 0.76 ppb in the presence of p ‐methylene blue (V). The chelating agent 2‐(5‐bromo‐2‐pyridylazo)‐5‐diethylaminophenol(VII) can be used to determine Cd 2+ ,Zn 2+ and Pb 2+ using the AdSV technique down to LODs of 9.3, 2.7 and 6.3 ppb, respectively. Several of these methods have been combined in the development of an automated method for the determination of trace Zn, Cd, Pb and Cu in an artificial river water matrix. The accuracy and precision of this procedure is discussed. Determination of Ni, Sn and As by this automated method and in such a matrix proved to be inaccurate.