Abstract

A simple reverse flow injection spectrophotometric determination of copper(II) was developed. The sensitivity enhancement of the reaction between copper(II) and pyrogallol red by cetyltrimethylammonium bromide, a cationic surfactant was then described. The formation of the ternary complex created a violet colour in an acetate buffer at pH 5.0 and exhibited absorption maxima at 600 nm. The optimum conditions of both chemical and flow injection parameters for the monitoring of copper(II) were found and examined. Experimental results showed a linear response over a concentration range of 0.035–4.5 mgL⁻¹of copper(II) with a correlation coefficient of 0.9997. The detection limit was 0.01 mg L⁻¹ and the repeatability was found to be 1.47% (n = 11, 1.0 mg L⁻¹copper(II). The proposed method was applied to the analysis of copper(II) in water samples as well as pharmaceutical samples, and the values obtained were in good agreement with the official AAS method at a 95% confidence level. The developed system was capable of producing a sampling frequency of 40 sample h⁻¹ and it is thus considered suitable for quantitating copper(II) in routine analysis.