2,2′,3,4-Tetrahydroxy-3′-sulpho-5′-nitroazobenzene for spectrophotometric determination of aluminium in pharmaceutical suspensions and granite

A selective and sensitive new spectrophotometric method has been developed for the determination of aluminium.2,2',3,4-Tetrahydroxyy-3'-sulpho-5'-nitroaobenzene (tetrahydroxyazon SN) formed an orange chelate with aluminium at pH 4. Molar absorptivity of the complex in 1:2 is 5.46 x 10(4) l mol(-1) cm(-1) at 479 nm. The method obeys Beer's law in the range of 0.005-1.079 mu g ml(-1). The determination of aluminium is not interfered with by earth alkaline, alkaline elements, rare earth elements, halides, phosphates, sulphates, urea, ascorbic acid, Sn2+, Sr2+, Cr3+, Cd2+, Hg2+, 'Mn2+. The proposed method is rapid and simple, and it has been succes or successfully applied to the determination of aluminium in certified pharmaceutieal suspension and granite. (c) 2005 Elsevier B.V. Ail rights reserved.