The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

The application of the hydrogen-palladium electrode (H2/Pd) as the indicator electrode for the determination of relative acidity scale (Es, mV) of tetrahydrofuran (THF) and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH), which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol) and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid) were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

Supplementary material for the article: Jevtić, S.; Stefanović, A.; Stanković, D. M.; Pergal, M. V.; Ivanović, A. T.; Jokić, A.; Petković, B. B. Boron-Doped Diamond Electrode — A Prestigious Unmodified Carbon Electrode for Simple and Fast Determination of Bentazone in River Water Samples. Diamond and Related Materials 2018, 81, 133–137. https://doi.org/10.1016/j.diamond.2017.12.009

Supplementary material for: [https://doi.org/10.1016/j.diamond.2017.12.009]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2081]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3177

Supplementary material for the article: Jevtić, S.; Stefanović, A.; Stanković, D. M.; Pergal, M. V.; Ivanović, A. T.; Jokić, A.; Petković, B. B. Boron-Doped Diamond Electrode — A Prestigious Unmodified Carbon Electrode for Simple and Fast Determination of Bentazone in River Water Samples. Diamond and Related Materials 2018, 81, 133–137. https://doi.org/10.1016/j.diamond.2017.12.009

Supplementary material for: [https://doi.org/10.1016/j.diamond.2017.12.009]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2081]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3177

Solid-State Synthesis of Silver Nanoparticles and Their Catalytic Application in Methylene Blue Reduction

The silver nanoparticles (Ag NPs) were successfully synthesized by a facile solid-state chemical method. Ag NPs were obtained by a mechanochemical reaction between silver nitrate and sodium citrate, with the constant stirring and heating of reactants. The size and morphology characterization of NPs powder was performed by scanning electron microscopy. The obtained NPs were spherical with a 36 nm average particle size diameter. UV-Vis spectroscopy, dynamic light scattering, and zeta potential measurements were used in order to characterize the surface plasmon band position in colloid dispersion and the NPs charges. Obtained NPs were utilized as a catalyst in the process of methylene blue (MB) reduction in the presence of sodium-borohydride. Kinetic measurements of uncatalyzed and catalyzed reduction were carried out using the stopped-flow technique, keeping the concentration of reactant constant. Mechanism of MB reduction in the presence of catalyst Ag NPs is elucidated as a consecutive two first-order reactions. The results of these studies support the hypothesis that NPs participated in electron transfer

Boron-doped diamond electrode - A prestigious unmodified carbon electrode for simple and fast determination of bentazone in river water samples

Bentazone (BZ) is selective contact-past herbicide with suspected reproductive toxicity potential for human due to possible contamination of ground and surface waters. This work presents simple, rapid, sensitive and accurate determination of bentazone at unmodified boron-doped diamond electrode, using differential pulse voltammetry in Britton-Robinson buffer (pH 4, oxidation peak at 1.0 V). Under optimized DPV conditions linear calibration curve was obtained for range of 2 to 100 mu M, with a detection limit of 0.5 mu M. The effect of possible interfering agents is negligible, confirming good selectivity of the method. The method was successfully applied to determination of bentazone in spiked river water samples. This electrochemical determination of bentazone represents a favorable alternative to other used time-consuming and expensive analytical techniques and procedures.Peer-reviewed manuscript: [http://cherry.chem.bg.ac.rs/handle/123456789/3177]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3178

Chemometrics based on the mineral content as a tool for the assessment of the pollution of top soils

This is the first research of this type which includes the wider area of Kosovo taking into account the mineral wealth. The concentrations of 20 elements: Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Se, Si, V, and Zn were determined using ICP-OES. The ranges of concentrations of toxic elements are lead (Pb) 0.044-14.98 g/kg, arsenic (As) 0.007-0.33 g/kg, cadmium (Cd) 0.004-0.044 g/kg, and chromium (Cr) 0.053-0.245 g/kg. The spatial distribution of toxic elements was described using distribution maps. Principal component and cluster analyses were performed to reveal grouping of samples