Cathodic stripping voltammetry of nickel on boron-doped diamond

The evaluation of the Ni(III)/Ni(II) transition as a means to quantify the concentration of nickel in an electroless nickel deposition bath has been carried out. The methodology relies on the electrodeposition of Ni onto a boron-doped diamond electrode and the subsequent oxidative conversion of the metallic layer to Ni(III). The analytical signal was derived from a cathodic stripping protocol in which the reduction of the Ni(III) layer to Ni(II) was monitored by the use of differential pulse voltammetry (DPV). Two hydrodynamic methods, with solution stirring and with electrode rotation, were used to enhance the mass transfer from solutions to the electrodes. The electrode recovery on the basis of the removal of the nickel hydroxide layer was performed in 0.1 M H2SO4. The stripping peaks obtained with both solution stirring and electrode rotation were observed at +0.6 V (vs SCE) with the response found to be linear over the range 0.3–5 μM (solution stirring) and 0.1–4 μM (electrode rotation). The viability of the technique was evaluated through the determination of nickel in an electroless nickel deposition bath solution used practically and validated by an independent comparison with the result of ICP-AES.