Application ofL-Dopa as an Electroactive Ligand for Indirect Determination of Aluminum in Biological Samples by Differential Pulse Voltammetry

A simple indirect method making use of 3,4-dihydroxyphenylalanine (L-dopa) as an electroactive complexation ligand for the determination of aluminum in biological samples at neutral pH on glassy carbon working electrode with differential pulse voltammetry (DPV) is reported. This method relies on the linear decrease of the DPV anodic peak current of L-dopa with the concentration of aluminum added. Under the optimum experimental conditions (pH 7.0, 0.08 M NH4Ac buffer solution, and 6×10−4 M L-dopa), the linear range is 1–16×10−6 M AlIII. The detection limit is 8.9×10−7 M and the relative standard deviation for 8.0×10−6 M AlIII is 3.9 % (n=8). Interference of foreign species relating to biological system has been inspected. The method has been applied to the measurement of aluminum in biological samples such as urine, hair, pork organs and consumption like drinking waters and synthetic renal dialysate. The possibility of the future application for in vivo detection of aluminum is also discussed.