Electrode Paste can be found in numerous industries, including those that manufacture steel, aluminium and ferroalloys. Its unique composition consists of calcined petroleum coke, electrically calcined anthracite coal, coal tar pitch, and other additional materials that provide exceptional properties that enhance performance and efficiency. Electrode paste, just like any other working electrode material has its own drawbacks. These should be considered before implementing it. Some of the biggest drawbacks include sensitivity towards contamination, a limited pH range and mechanical instability.
Contamination: Carbon-paste electrodes are susceptible to contamination. This is especially true when they are used in corrosive conditions. This can result in interference and inaccurate measurements. In addition, the surface of a carbon paste electrode can be prone to adsorption of species from the sample matrix, which can also cause errors in results.
Limitation of pH range: Certain compounds may be harder to analyze when using a carbon-paste electrode, depending on the type and degree of chemistry. As an example, acidic analytes may reduce the carbon dioxide generated by the electrode when reduction reactions are taking place, thus obscuring the signal.
To overcome these limitations, several research groups are focusing on the development of carbon paste electrodes that have been chemically modified. These modified electrodes have the potential to detect a wider range of analytes. Carbon paste electrodes (CPE), which are easy to prepare, have a large surface area that can be modified, and a relatively wide potential window.
CPEs can be improved to detect specific substances, like heavy metals, by adding various modifying chemicals. It is done by attaching different ligands on the surface of the carbon paste. The ligands can be organic polymers (polymers), inorganic Ion Exchangers and Nanoparticles.
In general, carbon-paste electrodes are used to analyze electroanalytical information, mostly because they have excellent sensitivity. They also make for an easy experiment. CPEs are difficult to characterize because they change their properties when exposed to various environmental conditions. For this reason, the characterization of carbon pastes has received a lot of attention, with many studies focusing on the effect of the modifier composition on the voltammetric response.
In an aqueous Pb(II) solution, we investigated the voltammetric response of carbon paste electrodes that were unmodified or HDPBA modified. The peak currents for six different carbon pastes with HDPBA weight-to-weight ratios 2.5%, 5.0% 7.5% and 10.0% were measured and compared to a control electrode that was identically prepared.
The results indicated that the higher concentration of modifiers, the more current peak was generated by the carbon-paste electrode. This is due to the higher amount of carbon present in the electrode. More sites are available for ion exchanging. The lower content of modifiers resulted to a reduced peak current. This is due to the less coverage of carbon surfaces with conductive particles.
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