Pre-concentration and separation of copper with water-soluble polyvinyl alcohol) and acetone system prior to its spectrophotometric determination

摘要

A water-soluble poly(vinyl alcohol)-acetone system for the pre-concentration and separation of Cu~(2+)in environmental water samples has been developed. First, poly(vinyl alcohol) (PVA) was able to complex with Cu~(2+), and the reaction product, the copper-PVA complex, was precipitated in excess acetone. Sequentially, the precipitate was separated by decantation and dissolved in a minimum amount of water. Finally, the copper ions were determined by the sodium diethyldithiocarbamate spectrophotometric method. Some related parameters that might affect the recovery of the copper were investigated in detail. Under the optimum experimental conditions, the detection limit is 0.014 μg mL~(-1) and the linearity range is from 0.025 to 3.00 μg mL~(-1). The relative standard deviation (n=11) is 1.1%. The method was successfully applied to the analysis of copper in spring water, ground water, tap water, lake water and electroplating waste water. A possible mechanism of the method is also proposed.