Novel catalytic spectrophotometric procedure for the determination of trace-level aluminium

A novel catalytic procedure for aluminium(III) was proposed based on Al3+ catalyzed oxidation of gallocyanine by hydrogen peroxide in a hexamethylene tetramine-hydrochloric acid buffer medium. The calibration graph is linear in the range of 0-200 ng ml(-1), and the detection limit is 1.2 ng ml(-1). Most foreign ions do not interfere with the determination, except for Cr(VI), Cu2+, Fe3+. The interference of Cr(VI) could be eliminated by reduction to Cr(III), and those of Cu2+ and Fe3+ by extraction with dithizone-carbon tetrachloride and cupferron-chloroform solution, respectively. The procedure had been used to the determination of aluminium in human hair, China tea and water samples. The recoveries were 98.6-101.5%, and relative standard deviations (RSD) were 0.8-1.5%, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.