SPECIATION OF SB(III) AND SB(V) BY PH-CONTROL USING 3 INORGANIC ACIDS (HYDROCHLORIC, PHOSPHORIC AND SULFURIC)

A method is described for the speciation of Sb(III) and Sb(V) using HG-AAS. The efficiency of stibine generation using different pH, from Sb(III) and Sb(V) solutions, was tested. At high pH-values Sb(V) is not reduced to form stibine, Sb(III) being selectively determined. The three acids HCl, H2SO4 and H3PO4 at controlled pH were used to generate stibine, H3PO4 being the most satisfactory for antimony speciation. The interference of Sb(V) was studied for the case of Sb(III) determination with stibine generation in H3PO4 medium (pH 1.81). The speciation of Sb(III) and Sb(V) is possible up to a ratio of 1:9.