Adsorptive stripping voltammetry of nickel with 1-nitroso-2-napthol using a bismuth film electrode

A sensitive procedure is presented for the voltammetric determination of nickel. The procedure involves an adsorptive accumulation of nickel 1-nitroso-2-napthol (NN) complex on a bismuth film electrode prepared ex situ by electrodeposition. The most suitable operating conditions and parameters such as pH, ligand concentration (C_NN), adsorptive potential (E_ads), adsorptive time (t_ads), scan rate and others were selected and the determination of nickel in aqueous solutions using the standard addition method was possible. The adsorbed Ni-NN complex gives a well defined cathodic stripping peak current at −0.70 V, which was used for the determination of nickel in the concentration range of 10.0-70.0 μg L⁻¹ (pH 7.5; C_NN 6.5 μmol L⁻¹; E_ads −0.30 V; t_ads 60 s) with a detection limit of 0.1 μg L⁻¹. The relative standard deviation for a solution containing 10.0 μg L⁻¹ of Ni(II) was 3.5% (n = 4). The proposed method was validated determining Ni(II) in certified reference waste water (SPS-WW1) and Certified Reference Water for Trace Elements (TMDA 51.3) with satisfactory results. Then lake water samples were analyzed.