Novel preconcentration technique for trace metal ions by aggregate film formation. Spectrophotometric determination of copper(II)

A highly sensitive method for the determination of copper(II) based on preconcentration of copper(II)-N,N–diethyldithiocarbamate as a aggregate film is described. Traces of copper(II) were quantitatively collected into a thin film consisting of hexadecyltrimethylammonium chloride (cetyltrimethylammonium chloride) and sulfosalicylic acid. The film is easily detached from a membrane filter support and the copper(II) complex was determined spectrophotometrically by dissolving in N,N-dimethylformamide. The calibration graph linear from 1.6×10−9 to 8×10−8 mol copper(II) in 14 ml of test solution. The relative standard deviation was 3.1% (n=5) at 3×10−6 M copper(II). The membrane filter could be used repeatedly. The method was applied to the determination of trace copper(II) added to river water.