Screen-Printed Carbon Electrode Modified with Carbon Nanotubes and Copper Film as a Simple Tool for Determination of Trace Concentrations of Lead Ions

A copper film-modified, carboxyl-functionalized, and multi-walled carbon nanotube (MWCNT-COOH)-modified screen-printed carbon electrode (CuF/MWCNTs/SPCE) was used for lead determination using anodic stripping voltammetry. The main parameters were investigated and optimized during the development of the research procedure. The most optimal electrolyte concentrations were determined to be 0.4 M HCl and 6.3 × 10−5 M Cu(II). The optimal parameters for voltammetric stripping measurements are as follows: an accumulation potential of −0.7 V; an accumulation time of 120 s; and a pulse amplitude and pulse time of 120 mV and 2 ms, respectively. The effect of surface active substances and humic substances as potential interferents present in aqueous environmental samples was investigated. The validation of the procedure was carried out using certified reference materials, like waste water SPS-WW1 and environmental matrix TM-25.5. In addition, the developed procedure was applied to investigate lead recovery from natural environmental water, such as rivers and lakes

Investigation and elimination of surfactant-induced interferences in anodic stripping voltammetry for the determination of trace amounts of cadmium

This article aims to investigate in detail to what extent surfactants affect the determination of cadmium by anodic stripping voltammetry. In recent years, the production and use of surfactants have been steadily increasing, so that their concentration in environmental water samples is rising. At the same time, it is known that organic compounds, such as surfactants, often hinder the voltammetric determination of trace elements by stripping. Non-ionic (Triton X-100, Brij 35, Tween 20, Tween 60, Tween 80), cationic (CTAB, CTAC, DTAB, HPC) and anionic (DSS, SDS) compounds were selected to investigate the effect of surfactants on the voltammetric signal of cadmium. At the same time, the extent to which the addition of Amberlite resins to the analysed solution eliminates the interfering effect of surfactants was tested. Three types of Amberlite resins XAD-2, XAD-7 and XAD-16 were selected for the study and the ratio of resin weight to solution volume was determined. Finally, the determination of cadmium in surfactant-enriched environmental samples was carried out. The recoveries obtained between 95.5 and 107%, with RSD between 3.4 and 6.2%, confirm the validity and correctness of the proposed procedure All measurements were carried out by anodic stripping voltammetry using a CNTs/SGC electrode modified with a bismuth film as the working electrode

An Electrochemical Sensor for the Determination of Trace Concentrations of Cadmium, Based on Spherical Glassy Carbon and Nanotubes

The practical application of a novel, eco-friendly electrochemical sensor based on low-dimensional structures, spherical glassy carbon microparticles, and multiwall carbon nanotubes is described. This sensor, modified with a bismuth film, was used for the determination of Cd(II) by the anodic stripping voltammetric method. The instrumental and chemical factors influencing the sensitivity of the procedure were thoroughly investigated and their most favorable values were selected (acetate buffer solution pH = 3 ± 0.1; 0.15 mmol L−1 Bi(III); activation potential/time: −2 V/3 s; accumulation potential/time: −0.9 V/50 s). Under the selected conditions, the method exhibited linearity in the range of 2 × 10−9 to 2 × 10−7 mol L−1 Cd(II) with a detection limit of 6.2 × 10−10 mol L−1 Cd(II). The results obtained also showed that the application of the sensor for Cd(II) detection did not experience any significant interference in the presence of a number of foreign ions. The applicability of this procedure was evaluated using TM-25.5 Environmental Matrix Reference Material and SPS-WW1 Waste Water Certified Reference Material as well as river water samples through addition and recovery tests