SOLUBILIZATION OF DITIZONE AND ITS MERCURY, LEAD AND CADMIUM COMPLEXES IN MICELLAR MEDIUM AND ITS APPLICATION IN SPECTROPHOTOMETRIC ANALYSIS

Abstract

This work reports on the solubilization of dithizone and some of its metal complexes in aqueous medium by the addition of the nonionic surfactant Triton X-100 stabilized with hydrochloric acid, and studied by means of their molecular absorption spectra in the visible. This property was used for the spectrophotometric analysis of mercury (II), lead (II) and cadmium (II), obtaining their molar absorptivities (Hg(II): 72 000, Cd (II): 41 000), optimal pH ranges (Hg(II): 1 — 4, Pb(II): 4.5 — 8.5, Cd(II): > 13), linear range (Hg(II): 0 — 3.3 ppm, Pb(II): 0 — 1.9 ppm, Cd(II): 0 — 0.6 ppm) and stability over time. This method is an alternative to the classic solvent extraction methods, and is also advantageous because it is faster, less tedious, eliminates the use of toxic organic solvents and is less expensive. The method tested is also applied to the analysis of Cd(II) dissolved in the waters of the Rimac River.