Abstract
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 electrodepos-
ition 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, 3r) and quantification (DL, 10r) limits inpure water were 2.01·108 and 6.7·107mol L1, respectively. The reproducibility of the
proposed method was determined from five different measurements in a solution containing2.2·10 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.