Flotation-spectrophotometric method for the determination of mercury using iodide and brilliant green

This paper describes a sensitive spectrophotometric method for the determination of mercury, based on the flotation of a mercury iodide-brilliant green complex with cyclohexane at pH 5 and dissolution of the complex in acetone. The absorbance of the complex is measured at 625 nm. Beer's law is obeyed from 4–500 g/l of mercury. The method is highly sensitive ( = 5.96 × 10⁵ 1 mol^–1 cm^–1) and selective, as it is free from interferences by almost all cations and anions in the presence of EDTA. Furthermore, a two-level orthogonal array design as a chemometric method has been used for optimization of the various parameters involved. The method has been successfully applied to paper industry effluents.