The demand for cobalt‐based alloys has been steadily increasing due to advancements in industrial and cutting‐edge technologies, particularly in metallurgy, where cobalt plays a crucial role in high‐performance superalloys, battery production, and corrosion‐resistant materials. Consequently, the concentration of cobalt ions in wastewater and environmental samples has exceeded permissible levels, raising significant ecological concerns. This study presents the development of an efficient method for the determination of cobalt(II) ions using a silver/mercury film working electrode (Hg(Ag)FE) modified with the organic dye ortho-nitrosophenol (o‐NF) through cyclic voltammetry (CV). Optimization of the experimental conditions revealed that an acetate buffer (0.1 M, pH 5.1) served as the supporting electrolyte, with an accumulation time of 10 s and a concentration of 2.0 μM o‐nitrosophenol. The preconcentration conditions were adjusted to enhance the sensitivity and selectivity for cobalt(II) ion detection. The method exhibited a linear relationship in the concentration range of 0.040–0.160 μM ( R ² = 0.9863), with a limit of detection (LOD) of 0.010 μM and a limit of quantification (LOQ) of 0.034 μM for Co(II) ions. The proposed method was successfully applied to the analysis of water samples from the Aydar–Arnasoy Reservoir, and the accuracy of the results was statistically validated using Student’s t ‐test. These findings demonstrate the potential of the developed method as an effective tool for environmental monitoring and the determination of cobalt ions in ecological protection initiatives.

A simple and cost-effective graphite paste electrode modified with 5-(4-aminophenyl)-4-amino-1,2,4-triazole-3(2H)-thione was developed for the selective voltammetric determination of Cu(II) ions in environmental water samples. The N,S-donor ligand was incorporated into a graphite–polystyrene matrix without the use of nanomaterials, providing a reproducible and straightforward electrode fabrication route. Scanning electron microscopy revealed a rough, porous surface morphology with an enhanced electroactive surface area of 0.065 cm², approximately twice the geometric area. Electrochemical impedance spectroscopy confirmed diffusion-controlled mass transport, while cyclic voltammetry indicated quasi-reversible behaviour of the Cu(II)/Cu(0) redox system with a linear dependence of peak current on the square root of the scan rate. Differential pulse voltammetry under optimised conditions (0.1 mol·L⁻¹ H₂SO₄, pH 1.0–1.2) yielded a linear analytical response over the concentration range of 0.01–0.4 μmol·L⁻¹ (R² = 0.99507), with a limit of detection of 0.02 μmol·L⁻¹ and a limit of quantification of 0.06 μmol·L⁻¹—well below the WHO guideline for copper in drinking water. The sensing mechanism involves selective N,S-bidentate coordination of Cu(II) at the electrode surface, followed by electrochemical reduction, as supported by FT-IR spectroscopic evidence. The sensor demonstrated good selectivity toward Cu(II) in the presence of common interfering metal ions at up to 20-fold excess. The method was successfully validated against ICP-OES (recovery 99.8%, RSD < 0.33%) and confirmed by spike–recovery experiments (99.0–99.5%), confirming its practical applicability for trace-level environmental monitoring. The modified electrode retained approximately 93% of its initial response after 30 consecutive measurements and 91% after 14 days of storage, demonstrating good operational stability.

Indium-based nanoparticles - metallic indium, indium oxide (In₂O₃), indium tin oxide (ITO), indium-doped oxides, indium chalcogenides and indium-containing quantum dots - combine tunable band gaps, oxygen-vacancy-controlled conductivity and luminescence, and plasmonic responses extending from the ultraviolet to the infrared. Although In₂O₃ nanoparticles have received far less attention than ZnO or TiO₂, they are emerging as promising materials for biomedicine, chemical sensing, photocatalysis and optoelectronics. This review compares physical (solvated metal atom dispersion, pulsed laser ablation, laser/electron irradiation), solution-chemical (thermolysis, hydrothermal, solvothermal, sol– gel auto-combustion, hot injection), electrochemical (ionic-liquid and aqueous electroreduction) and plant-mediated synthesis routes, with emphasis on green synthesis using Aloe vera, Aerva javanica, Artemisia vulgaris, Vitis vinifera and green tea extracts. The roles of oxygen vacancies, dopants and composition in determining optical and electronic properties are discussed. Applications are surveyed, including antibacterial and anticancer activity, photothermal and photoacoustic theragnostic, drug delivery with SPECT imaging, quantum- dot-based biomarker detection, ethanol and humidity sensing, ITO-based electrochemical sensing, dye photodegradation and heterogeneous organic catalysis.

Improving the shelf life and quality of baked products without compromising their sensory attributes remains a key challenge in the food industry. In this study, the density of sodium dihydropyrophosphate (Na₂H₂P₂O₇) solution at various concentrations in a water–glycerol binary system was measured using an Anton Paar DMA 4500 M vibrating tube densimeter, across a temperature range of 283.15 to 343.15 K, at 5 K intervals. Based on the density data, the molal volume (Vϕ), hydrolysis constant, and degree of hydrolysis for a 0.05 M solution in 0.1% water–glycerol medium were found to decrease by up to 10 times. This decrease resulted in a significant reduction in Gibbs free energy, indicating a suppression of chemical reactivity. The findings suggest that glycerol not only enhances the preservative properties of sodium dihydropyrophosphate but also contributes to improved porosity in baked goods. Therefore, such binary systems may be promising for improving food product stability and structure.

This study presents the development and experimental substantiation of a sorption-based process for selective lithium recovery from highly mineralized brines. The process integrates alkaline precipitation of interfering cations with dynamic sorption using acetophosphate cellulose as a selective sorbent. The static exchange capacity of the developed sorbent was determined as 25.48 mg/g, with lithium desorption efficiency reaching 98.25% and sorbent stability maintained through 10 consecutive sorption-desorption cycles (93% capacity retention). The process demonstrates selective lithium extraction under moderate temperature conditions without toxic organic solvents, providing a scientific foundation for subsequent technological development and pilot-scale implementation. The results demonstrate both scientific significance and technological applicability of the proposed process.