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Abstract

The work deals with the optimization of the conditions for the spectrophotometric determination of mercury using copper(II) diethanoldithiocarbamate [Cu((HOCH₂CH₂)₂NCS₂)₂] (I). The determination is based on replacement of Cu²⁺ ions by Hg²⁺ ions in complex I in acidic aqueous acetone medium and measuring the decrease in the absorbance at the absorption maximum of complex I (λ = 440 nm). The statistical importance of the factors affecting the analytical signal (absorbance) was found by the analysis of variance. The analytical signal is affected most by the pH value, the concentration of Cu²⁺ ions, and the acetone content. The best results were obtained at pH ~ 2 and an acetone content of 15% (v/v). The analytical calibration curve is nonlinear. The determination limit is 50 μg Hg in 1 dm³. The method is useful for the rapid determination of mercury with a precision of ± 5% in colourless solutions not containing Cu²⁺ or Ag⁺ ions or strong oxidants.