Electrochemical determination of mercury (Ⅱ) using NaPb_(4-x) Cd_x(PO_4)_3 (0 ≤ x ≤ 2) modified graphite electrode: application in fish and seawater samples

摘要

The aim of this work is the synthesis of a new series of lacunar apatite NaPb4-xCdx(PO4)(3) (0 = x = 2) by the solid-state reaction, in which the substitution was selected between cadmium and lead. These powders were crystallised in the hexagonal system, space group P6(3)/m. The characterisation of apatite powders was carried out using X-ray powder diffraction, Infrared and Raman spectroscopy. The prepared apatite was used as a modifier of carbon electrode for mercury (II) analysis using differential pulse anodic stripping voltammetry. The best distribution of apatite has been selected in terms of high electrochemical response of mercury oxidation. The obtained results show excellent linear calibration curves in the range of 9.0 x 10(-7 )- 1.0 x 10(-4) mol L-1 with a detection limit of 1.35 x 10(-8) mol L-1. The selectivity of this electrode was evaluated in the presence of other metal ions. Furthermore, the analytical methodology was then successfully applied to monitor mercury in fish and seawater samples.