Flame Atomic Absorption Spectrometric Determination of Cobalt(II) after Extraction and Preconcentration on to Modified Analcime Loaded with Zincon

Abstract

A simple, rapid, sensitive flame atomic absorption spectrometry method has been developed for the determination of trace amount of cobalt(II) in various samples after absorption of its 2-[1-(2-hydroxy5-sulfophenyl)-3-phenyl-5-formazano] benzoic acid monosodium salt (zincon) complex on modified Analcime by column method in the pH range 5–9 at flow rate 3 m min^–1. The retained analyte on the analcime with recovered with 10.0 mL of 2 M hydrochloric acid solution and determined by flame atomic absorption spectrometry. Detection limit is 8 ng mL^–1 and calibration curve is linear in the range of 0.02–3.8 μg mL^–1 in final solution with correlation coefficient of 0.9997. Eight replicate determinations of 1.5 μg mL^–1 cobalt in final solution give absorbance of 0.140, with relative standard deviation of ± 1.2%. The interference of a large number of anions and cations has been studied and the proposed method was used for determination of cobalt in various water and standard samples. Determination of cobalt in standard samples indicated that the proposed method has good accuracy.