Determination of copper in concentrated matrices by flow injection with inductively coupled plasma atomic emission spectrometry

Abstract

Determination of copper in solutions containing various sulphate compounds, such as H₂SO₄, Na₂SO₄, K₂SO₄, MgSO₄ and ZnSO₄ at concentrations up to 200 g l^–1 are reported. The chosen technique was flow injection inductively coupled plasma atomic emission spectrometry. Of the materials mentioned above, ZnSO₄ has a particularly strong influence on the copper emission. At slow carrier flow-rates, increased solution viscosity leads to peak broadening and reduced peak height. As carrier flow is increased, peaks sharpen and these viscosity effects are overcome. Thus, at a flow-rate of 13.2 ml min^–1, copper peaks in either aqueous or high salt matrices are not significantly different in height.

The method developed has been applied to the determination of copper in a Burt filtrate taken from a zinc plant, a solution high in sulphate salts. Flow injection using both a standard calibration plot and the standard additions method has been applied to the filtrate. The procedure has been shown to offer advantages in speed over an existing xanthate technique, which relies on copper precipitation to separate it from interferences, with re-dissolution prior to analysis. The precision of the method is generally better than 8% RSD, with copper recoveries of 90–115%.