Spectrofluorimetric determination of molybdenum in vegetal tissues and a pharmaceutical compound with Alizarin Red S in micellar medium

A sensitive method for the spectrofluorimetric determination of Mo with Alizarin Red S, in the presence of hexadecyltrimethylammonium bromide, is described. The complex is formed at pH 4.7 in micellar medium, and the fluorescence intensity develops immediately. The detection limit is 1.7 ng cm–3 and the linear range is between 6 and 1000 ng cm–3. The influence of several ions, as interferents, is discussed. The proposed method has been applied to the determination of Mo in vegetal tissues and in a pharmaceutical compound.