Homogeneous Liquid–Liquid Extraction and Determination of Cobalt, Copper, and Nickel in Water Samples by Flame Atomic Absorption Spectrometry

Abstract

A simple and effective homogeneous liquid–liquid extraction method has been used for the simultaneous extraction and preconcentration of cobalt, copper, and nickel after the formation of complex with 4‐benzylpiperidinedithiocarbamate potassium salt (K‐4‐BPDC), and later they were determined by flame atomic absorption spectrometry (FAAS) using (water/tetrabutylammonium ion (TBA+)/chloroform) as a ternary component system. The phase separation phenomenon occurred by an ion‐pair formation of TBA+ and perchlorate ion. After the optimization of complexation and extraction conditions ([K‐4‐BPDC]=2.0×10−4 mol l−1, [TBA+]=2.0×10−2 mol l−1, [CHCl3]=60.0 µl, [ClO4 −]=2.0 ×10−2 mol l −1 and pH=6.0), a preconcentration factor of 200 was obtained for only 10 ml of the sample. The analytical curves were linear in the range of 20–1500, 15–2000, 35–1600 µg l−1 and the limits of detection were 10, 5, and 15 µg l−1 for Co2+, Cu2+, and Ni2+, respectively. The proposed method was applied for the extraction and determination of Co2+, Cu2+, and Ni2+ in natural water samples with satisfactory results.