Analytical & Bioanalytical Electrochemistry
Volume:15 Issue: 6, Jun 2023

A potentiometric sensor as a selective, straightforward, and sensitive device was prepared based on a carbon paste electrode (CPE) as an indicator electrode for determining manganese (II) ions in environmental water and biological samples. A novel and synthetic ligand, 5,5'-((2E,2'E)-2,2'-(1,2-diphenylethane-1,2-diylidene)bis(hydrazin-1-yl-2-ylidene))bis (4-amino-4H-1,2,4-triazole-3-thiol) (called BBP), which has a selective interaction with Mn2+ ion, was chosen as an ionophore in the CPE composite. An optimal mixture design was generated to optimize the CPE components' percentages, including BBP, MWCNTs, an ionic liquid, and graphite powder, and to investigate binary interactions between the component amounts. Effects of several modifier agents, such as MWCNTs, NH2-MWCNTs, and COOH-MWCNTs, were evaluated in the CPE composite. The ability of two binders (Paraffin oil and an ionic liquid ([Bmim][BF4])) in the CPE composite was compared, indicating that ionic liquid has a better response than paraffin oil due to an increase in electrical conductivity and flexibility of CPE. Under the CPE components optimization, the sensor displayed a wide pH range from 2.8 to 8.2, a short response time (5 s), and a long lifetime (11 weeks) for the Mn2+ ion determination. The sensor also has a wide linear range from 1.0×10-7-1.0×10-1 M with a LOD of 3.1×10-8 M and an R-squared of 0.998 without significant interfering effects of other ions for the Mn2+ ion measurement. The sensor performance was studied by analyzing river water, well water, and human urine samples, and the results were compared with flame atomic absorption spectrometry.

This article reports a detailed report of the synthesis and depiction of iron oxide nanomaterials (FeONPs) and their electroanalytical application. Electrochemical examination of Guanine (GU) and Dopamine (DA) is performed by synthesized iron oxide nanoparticles modified with carbon paste electrode (CPE) using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. Peak potential of GU along with DA at FeOMCPE are 0.76 and 0.14V respectively. A good linear response was obtained by CV of GU and DA, in the concentration ranges 10-70 and10-70 μM respectively and the LOD value for GU along with DA was observed to be 5.3 and 4.6 μM. The result shows that the FeOMCPE exhibited good analytical performance and high electro-catalytic activity of DA and GU.

In this work, we evaluated the potential of combining Fenton's reagent and biological treatment to remove persistent pharmaceutical pollutants, specifically sertraline hydrochloride (SER-HCl) with a view to mineralizing it in an economical and ecological way. A single-compartment batch reactor containing a carbon felt cathode and a platinum anode was used to perform the electro-Fenton pretreatment of SER-HCl. GC-MS and LC-MS were used to identify the intermediate by-products and thus to suggest a probable path of degradation. In addition, tracking of inorganic ions as well as the nitrogen and chloride molecules liberated during SER-HCl electrolysis was determined by ion chromatography. Then, the continuous aerobic degradation of SER-HCl, was studied for a period of 21 days at around 25 °C. A complete degradation of SER-HCl (0.1 mM) was noted at 400 mA after 5 min of electrolysis. In addition, an improvement in the BOD5/COD ratio was observed from an initial value of 0.042 to 0.33 and 0.47 over 1.5 and 2 hours of electrolysis respectively. The solution should be biodegradable after 1.5 hours of electro-Fenton pretreatment, from which the pharmaceutical product oxidized to readily biodegradable compounds, mostly short-chain carboxylic acids, which are available for uptake by microorganisms. In this point, a biological process of the electrolysis co-products after 1 h and 30 min, and 2 h was then performed aiming at biodegrading the remaining products. As a result, the COD yield increased slightly throughout the 21 days to 90.7% and 94.2% for 1 h30min and 2 h, respectively, showing the suitability of the proposed coupled process.

This research has successfully created a carbon paste electrode that has been modified with nitrogen-sulfur-doped graphene oxide, allowing for the accurate detection of chromium ions in aqueous solutions. The surface morphology of the modifier was investigated by FT-IR and SEM.  Through the use of anodic stripping differential pulse voltammetry, the electrochemical response of the modified carbon paste electrode to chromium ions has been analyzed and shown to exhibit an excellent electro-oxidation response when exposed to chromium ions. The linear dynamic range of chromium analysis produced a remarkable sensitivity of 0.1986 between 0.01 and 10 nM, with a sensitivity of 0.2048 between 10 and 125 nM. The detection limit was found to be 4.58 pico-molar. In a real sample, the electrode was able to measure chrome (VI) with results comparable to other techniques used in measuring chrome (VI). This achievement highlights the possibilities of utilizing innovative technology to create solutions that can address real-world problems.

To develop proton exchange membrane blends based on polybenzimidazole (PBI), a novel polymer blend membrane consisting of PBI and sulfonated poly 1,4-phenylene ether ether sulphone (SPEES) was prepared by solution casting method. The goal of the work was to study the performance of the acid-base composition on its properties, such as mechanical stability, thermal stability, and proton conductivity of PBI-SPEES blend membranes. The N−H···O interactions between the PBI and SPEES in the blend membranes indicated that the two polymers form a miscible blend. The acid uptake (12 moles) and proton conductivity (101 mS/cm in 160 °C) of the blend membranes were significantly ameliorated as compared to pure phosphoric acid-doped PBI (APBI) membranes. A single glass transition value of PBI-SPEES blend membranes which were between the glass transition value of the PBI and SPEES membranes confirmed the miscible properties of PBI-SPEES blend membranes. The presence of SPEES in the blend membranes decreases the friability and hardness and increases the flexibility and proton conductivity of APBI membranes. According to the PEM fuel cell results, with a high-power density of 0.65 W/cm2 at 180 ºC, the PBI-SPEES blend membranes have a high potential for use as an appropriate membrane in the fuel cells.

The goal of this study is to establish a simple and convenient co-precipitation approach for the ultrasonic synthesis of NiMoO4/Mn(VO3)2 heterostructures without capping agents and to adapt the glassy carbon electrode with this material for electrochemical detection of dopamine. To analyze the chemical structure and morphology of nanostructures, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) techniques were used. The ultrasonic wave for pure NiMoO4/Mn(VO3)2 heterostructures with homogeneous sphere-like shape and small particle size around 30-40 nm was discovered using FESEM and XRD results. Electrochemical sensors have been sought after for studying biological, environmental, and pharmaceutical species due to their long-term reliability, high sensitivity, and accuracy, as well as their low cost, speed, and ease of shrinking. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were used to conduct electrochemical experiments of the GCE/NiMoO4/Mn(VO3)2 towards dopamine (DA) detection. According to the DPV results, the modified sensor revealed a linear concentration range of 1 to 60 μM with a limit of detection of 0.33 M and high selectivity.