Enhanced voltammetric waves of iron(III)—EDTA at a chitin-containing carbon paste electrode and its analytical application
✍ Scribed by Zhu-Ping Bai; Toshio Nakamura; Kosuke Izutsu
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 405 KB
- Volume
- 2
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
A chitin-containing carbon paste electrode was found to give highly sensitive voltammetric waves for Fe(II1)-EDTA chelate both in cyclic voltammetry (CV) and in differential pulse voltammetry (DW). Various conditions for the determination of trace Fe(II1) were studied. The optimum chitin content in the carbon paste (graphite powder : mineral oil = 2 : 1) was 6% (by weight). In a solution of 0.01 M KCI and 3 X M EDTA (pH 3.0), the DW peak potential for the reduction of Fe(II1)-EDTA was -0.05 V vs. AgIAgCl. The peak current was proportional to the Fe(II1) concentration between 2 X lo-' and 6.5
x M Fe(II1) was 2.6%. The method was fairly free from interference and could be applied to the determination of iron in both river and tap water. M; the relative standard deviation for 2 X WRODUCTION Recently, mixed-carbon paste electrodes made of carbon pastes doped with modifying molecules are gaining popularity as voltammetric indicator electrodes. Some modified carbon paste electrodes have catalytic activities, and others are effective to preconcentrate trace electroactive substances before their voltammetric determinations [ 1-41. Wang et al. [ 51 used a carbon paste electrode modified with a cation-exchange resin to preconcentrate cations. Abruna et al. [6] used a carbon paste electrode modified with 1 ,lo-phenanthroline in the determination of cobalt(I1). Halbert and Baldwin [7] showed that a cobalt-phthalocyanine-containing carbon paste electrode was effective in catalyzing the electrode reaction of sulfhydryl compounds.
Chitin is a cellulose-like biopolymer consisting predominantly o f poly(N-acetyl-l,4-P-D-glucopyranosamine). The ability of chitin and related compounds to concentrate trace metals have been previously used in spectrophotometric analyses [8, 91. In the present work, we used a chitin-containing carbon paste electrode and found that the electrode could give highly sensitive voltammetric waves for Fe(II1)-EDTA. From this, a differential pulse voltammetric method was developed for the determination of trace iron.