A New Spectrophotometric Method for Determination of Iron in Herbs, Spices and Beans with 2,6-Diacetylprydine Dioxime and 2-Acetylpyridine Monoxime
The reaction of iron (II) with 2, 6-diacetylprydine dioxime (H2dapd) and 2-acetylprydine monoxime (Hapm) in 10% and 60% v/v ethanol-water solution at pH 2.5 and 7.5, respectively, were studied using direct and first derivative spectrophotometry. Fe (III) is reduced by H2dapd and gives iron (II) complex. A simple, rapid, selective and sensitive method for the determination of Fe (II), Fe (III) and a mixture of them with the H2dapd reagent in acid water-ethanol medium after the solution attained to stand periods of 30 sec, 4 hr and 4 hr, respectively, are proposed. Hapm also reacts with Fe (II) to form [Fe(Hapm)3]2+ complex with less selectivity and sensitivity than H2dapm reagent. Calibration graph with [Fe(H2dapd)2]2+ is linear over the range 0.28 μg mLˉ1 with an apparent molar absorptivity of 8.481×103 L molˉ1cmˉ1 at λm 428 nm. Linear dynamic ranges are 0.01-11.0 and 0.07-11.0 μg mLˉ1 iron (II) as [Fe(H2dapd)2]2+ complex for direct and derivative modes, respectively. The analytical sensitivity is 4.44×10-3 μg mLˉ1 for direct and 9.15×10-5 μg mLˉ1 for derivative spectrophotometry with [Fe(H2dapd)2]2+ complex. First derivative method enhances the sensitivity of the Fe(H2dapd)2]2+ more than direct one with two folds for Ni2+, Co2+, Cu2+ and Cr3+. A linear equation was derived from iron (II) determining as Fe (H2dapd)2]2+ in the presence of synthetic solution containing Ni2+, Co2+, Cu2+ and Cr3+. The use of H2dapd reagent for the determination of total iron spectrophotometerically in foodstuffs, herbs, spices (rocks) after wet ashing (wet digestion) in the absence of reducing agent is compared with that employing AAS.
Copyright: © 2005 Z. R. Komy, E. A. Abu-Gharib and A. Desoky. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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- 6-diacetylprydine dioxime complex