Abstract: Electroanalytic direct determination of aluminum is a difficult subject because of the highly negative reductive potential of Al(Ⅲ) and interference of H⁺. But developing methods for the determination of trace amount of aluminum in environmental and biological samples is a hot topic in recent decades owning to the recognition of the potential toxic effects of aluminum. In this paper, the indirect differential pulse voltammetric(DPV) determination of aluminum with L-dopa(3,4-dihydroxyphenylalanine) on glass carbon working electrode has been reported. This novel method bases on the linear decrease of DPVanodic peak current of Ldopa with the concentration of aluminum added. Under the optimum experimental conditions (pH8.5, 0.08 mol/Lbuffer solution, 4×10^-4 mol/L Ldopa), the linear range and the detection limit are (2—18)×10^-7 and 7.6×10^-8 mol/L Al(Ⅲ) respectively, the relative standard deviation for 2×10^-5 mol/L Al (Ⅲ) is 2.4%(n=10). Anumber of foreign species, especially those necessary components in human body such as ascorbic acid, citrate, phosphate, Fe(Ⅲ), Fe(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Ca(Ⅱ) and Mg(Ⅱ) for interference have been studied. Satisfactory recoveries have been obtained by applying this method to determining aluminum in biological samples including mineral water, synthetic renal dialysate, urine and hair. The significance of the method and solutions to possible interference encountered in in vivo detection are discussed. Anew direction for further development of the in vivo determination of aluminum is provided in this studies.

Key words: L-Dopa(3,4-dihydroxyphenylalanine), Aluminum, Differential pulse voltammetry