Evaluation of a platinum electrode modified with hydroxyapatite in the lead(II) determination in a square wave voltammetric procedure

The behavior of a modified carbon platinum electrode (Pt) for lead(II) determination by square wave voltammetry (SWV) was studied. The modified electrode is obtained by electrodeposition of hydroxyapatite (HAP) on the surface of a bare platinum electrode. The new electrode (HAP/Pt) revealed interesting electroanalytical detection of lead(II) based on the adsorption of this metal onto hydroxyapatite under open circuit conditions. After optimization of the experimental and voltammetric conditions, the best voltammetric responses-current intensity and voltammetric profile were obtained in 0.2 mol L−1 KNO3 with: 30 min accumulation time, 5 mV pulse amplitude and 1 mV s−1 scan rate. The observed detection (DL, 3σ) and quantification (DL, 10σ) limits in pure water were 2.01 × 10−8 and 6.7 × 10−7 mol L−1, respectively. The reproducibility of the proposed method was determined from five different measurements in a solution containing 2.2 × 10−6 mol L−1 lead(II) with a coefficients of variation of 2.08%.The electrochemical of hydroxyapatite at platinum surfaces was characterized, after calcinations 900 °C, by X-ray diffraction, infrared spectroscopy, chemical and electrochemical analysis.