Determination of lead(II) in aqueous solution using carbon nanotubes paste electrodes modified with Amberlite IR-120

A new composite electrode is described for anodic stripping voltammetry determination of Pb(II) at trace level in aqueous solution. The electrode is based on the use of multiwalled carbon nanotubes and Amberlite IR-120. The anodic stripping voltammograms depend, to a large extent, on the composition of the modified electrode and the preconcentration conditions. Under optimum conditions, the anodic peak current at around -0. 57 V is linearly related to the concentration of Pb(II) in the range from 9. 6 x 10-8 to 1. 7 x 10-6 mol L-1 (R = 0. 998). The detection limit is 2. 1 x 10-8 mol L-1, and the relative standard deviation (RSD) at 0. 24 x 10-6 mol L-1 is 1. 7% (n = 6). The modified electrode was applied to the determination of Pb(II) using the standard addition method; the results showed average relative recoveries of 95% for the samples analysed. (author)