Potentiometric Stripping Analysis of Cadmium and Lead with Constant Inverse Current in the Analytical Step Using an Open Tubular Mercury-Coated Glassy Carbon Electrode

Abstract

The most important experimental parameters of the flow potentiometric stripping analysis (PSA) with oxygen as an oxidant were investigated and optimised. A simple, homemade flow system consisting of glassy carbon tubes, which served as a working and auxiliary electrode, was used. By applying a rest period before the stripping step (the flow stop mode) and by imposing a constant reductive current simultaneously with the interruption of potentiostatic control, significant increase of the flow PSA sensitivity was achieved. In the determination of cadmium and lead, quantitation limits of 0.11 and 0.82 μg/L were obtained. The precision of the method was evaluated in terms of repeatability and reproducibility, with values of relative standard deviation lower than 4.0% for cadmium and 4.2% for lead. This modified technique was applied for simultaneous determination of cadmium and lead in milk, after a simple pretreatment of the samples by dilution and acidification. The method accuracy was confirmed by analysing the certified reference material of skimmed milk powder (ERM-BD151).

Thiolated poly(aspartic acid)-functionalized two-dimensional MoS2, chitosan and bismuth film as a sensor platform for cadmium ion detection

“…22,23 However, the toxicity of mercury severely limits its applications in constructing sensors. 24,25 Therefore, bismuth, the less toxicity heavy metal, 26,27 is used for constructing sensors in this work. Except electrode materials, the sensing material also plays an important role in constructing sensors.…”

Electrochemical Sensors Based on Metal-Organic Framework and Conductive Polymer HKUST-1@PANI for High-Performance Detection of Lead Ions

“…13 Many techniques are used to the detection of heavy metal ions, which are divided into three classes. Electrochemical detection techniques (amperometry, voltammetry, potentiometry, impedance measurement and coulometry), 14,15 spectroscopic detection techniques (atomic absorption spectroscopy, atomic emission spectroscopy, inductively coupled plasma mass spectrometry) 11 and optical detection techniques (absorption, reflection or luminescence spectrometry). 16 Spectroscopy is highly sensitive, but unique and requires extensive preparation.…”