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Stripping Voltammetric Determination of Iodide with Synergistic Accumulation at a Carbon Paste Electrode
Author(s) -
Švancara Ivan,
Konvalina Jiří,
Schachl Klemens,
Kalcher Kurt,
Vytřas Karel
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(199805)10:6<435::aid-elan435>3.0.co;2-j
Subject(s) - iodide , chemistry , thiocyanate , detection limit , bromide , iodine , stripping (fiber) , inorganic chemistry , electrolyte , supporting electrolyte , halide , carbon paste electrode , extraction (chemistry) , electrode , electrochemistry , cyclic voltammetry , chromatography , materials science , organic chemistry , composite material
Carbon paste electrodes (CPEs) of various compositions were studied to elucidate the stripping voltammetric behavior of iodide. At an accumulation potential of +0.7 V (vs. Ag/AgCl), the CPE containing tricresyl phosphate as a pasting liquid was able to preconcetrate iodide effectively via ion‐pairing reaction followed by oxidation to iodine and its extraction onto pasting liquid. In a supporting electrolyte containing 0.5 M NaCl and 0.1 M HCl, the reduction signal was proportional to iodide concentration from 5 × 10 −6 to 5 × 10 −7 mol/L with a detection limit of approximately 2.5 × 10 −7 mol/L (accumulation for 5 min). Other halides and pseudohalides did not interfere with the determination, except for a high concentration excess of thiocyanate and bromide (100:1). The method was tested on model solutions and was applied to determine total iodine in samples of table salts and mineral water. The results were compared to those obtained by reference methods.