Spectrophotometric determination of trace copper with a Cu-diethyldithiocarbamate-β-cyclodextrin colour system

A simple, selective and accurate spectrophotometric method for determination of trace copper with diethyldithiocarbamate(DDTC) in the presence of β-cyclodextrin(β-CD) in ammonia media has been developed. The apparent molar absorptivity of Cu(II)-DDTC-β-CD inclusion complex is 1.3 × 10 4 1 · mole −1 · cm −1 at 436 nm, and Beer's law is obeyed for copper in the range 0–150 μg/25 ml. The detection limit is 4.38 × 10 −7 M( S/ N = 3). The proposed method has been successfully applied to the determination of copper in aluminium alloys, soils, millet, wheat flour, herbs, vegetables and some traditional Chinese herbal medicines with satisfactory results.