ENHANCED VOLTAMMETRIC WAVES OF IRON(III)-EDTA AT A CHITIN-CONTAINING CARBON PASTE ELECTRODE AND ITS ANALYTICAL APPLICATION

A chitin‐containing carbon paste electrode was found to give highly sensitive voltammetric waves for Fe(III)‐EDTA chelate both in cyclic voltammetry (CV) and in differential pulse voltammetry (DPV). Various conditions for the determination of trace Fe(III) 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 KCl and 3 × 10−4 M EDTA (pH 3.0), the DPV peak potential for the reduction of Fe(III)‐EDTA was −0.05 V vs. Ag/AgCl. The peak current was proportional to the Fe(III) concentration between 2 × 10−7 and 6.5 × 10−6 M; the relative standard deviation for 2 × 10−6 M Fe(III) 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. Copyright © 1990 VCH Publishers, Inc.