Sensitive Electrochemical Determination of Folic Acid Using ex–situ Prepared Bismuth Film Electrodes

The electrochemical behavior of folic acid (FA), at the electrochemically prepared ex situ bismuth film (BiF) on glassy carbon electrode, clearly indicates electrocatalytic nature of the prepared film toward FA reduction (at –0.55 V). Scanning electron microscopy is used for morphological characterization of the prepared BiF. Accordingly, we establishing an electrochemical procedure based on square wave cathodic stripping voltammetry, preceded by accumulation of FA on the BiF electrode (BiFE). This analytical method is optimized and its analytical performance is presented. This electrode displays a two linear response range: 0.1 to 1.0 μmol L–1 and 1.0–10.0 μmol L–1 with sensitivity of 20.10 μA μmol–1 L and 2.28 μA μmol–1 L, respectively. Developed method was validated in compliance with spectrophotometric method. Excellent recovery and standard deviation obtained with BiFE revealed great analytical potential of the proposed method which was applied for the determination of FA in pharmaceuticals formulation. This work is licensed under a Creative Commons Attribution 4.0 International License

Scientific Research Activities of the Department of General and Inorganic Chemistry in the Period 2010–2020

Od utemeljenja Zavoda, akademske godine 1961./62., njegova znanstveno-istraživačka djelatnost bila je usmjerena na elektrokemijska istraživanja metala, pojavu pasiviteta i inhibiciju korozije. Kasnije, ponajprije primjenom elektrokemijskih metoda, proučavaju se fenomeni na granici faza metal│anodni sloj│elektrolitna otopina koji su od značaja za kemijske izvore struje i poluvodičke sustave. Tijekom posljednjih deset godina istraživanja se usmjeravaju u dva smjera: i) ispitivanje utjecaja legirajućih elemenata na dizajn otpornih materijala i biofunkcionalizacija površine biorazgradljivih i biokompatibilnih metalnih implantata; ii) modifikaciju elektroda i njihovih površina u svrhu razvoja novih elektroanalitičkih metoda za određivanje teških metala i biomolekula. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.Since the establishment of the Department of General and Inorganic Chemistry in 1961, at the Faculty of Chemistry and Technology, University of Split, its scientific interest and investigations were focused toward electrochemical research. Consequently, electrochemistry became the backbone of the scientific research and development of the Department. In the last 10 years, scientific interest has been focused on the influence of alloying elements on design of corrosion resistance materials, as well as biofunctionalisation of biodegradable and biocompatible metal-based implants. In addition, development of various electroanalytical methods based on modified electrodes as sensing part of sensors, have been in focus in the recent period. The developed sensors were used for determination of heavy metals or biomolecules. This work is licensed under a Creative Commons Attribution 4.0 International License

Monthly and Seasonal Variations of NO2, SO2 and Black-smoke Located Within the Sport District in Urban Area, City of Split, Croatia

This paper represents, for the first time, scientific data as a part of monitoring air quality in the city of Split. The city has a problem with the air pollution mostly caused by anthropogenic activities and partly by natural origin activities. This study presents results of monthly and seasonal variations of NO2, SO2 and black-smoke as well as the influence of meteorological parameters on observed concentration levels. Average seasonal values for SO2 ranged from 22.54 to 54.81 g m–3, for NO2 from 48.24 to 56.38 g m–3 and for black-smoke from 4.15 to 5.64 g m–3. The results obtained for SO2 and black-smoke were below, while for NO2 were above the limit value of pollutants in the air recommended by Croatian Government (Air Protection Act (OG 178/04); Regulation on limit values of pollutants in air (OG 133/05)). As the result of stable meteorological conditions (high temperatures and drought), the increase in SO2 concentration was significant in summer period, while the concentrations of NO2 and black-smoke were not significantly changed during year and did not depend on other parameters. (doi: 10.5562/cca1966

Copper(II) ion selective PVC membrane electrode based on S,S\u27-bis(2-aminophenyl)ethanebis(thioate)

S,S\u27-bis(2-aminophenyl)ethanebis(thioate) (APhET) was synthesized and used as ion carrier in the preparation of copper(II) ion selective PVC membrane electrodes. The best performances were obtained by a membrane electrode with the composition: PVC as matrix (66 mg), APhET as ionophore (4 mg), o-NPOE as plasticizer (132 mg) and NaTBP as anionic additive (1/2 mole ratio in respect to APhET). This electrode exhibited a linear potential response to copper(II) in the concentration range 6.0 × 10−6 − 5.0 × 10−2 mol dm−3, with Nernstian slope of 29.5 mV/decade and detection limit down to 4 × 10−6 mol dm−3. It is suitable for copper(II) determination within pH between 4 and 7, and performs well over a period of 3 months. The electrode is selective for copper over a large number of metal ions, except Hg2+. No interference was noticed by chlorides and other examined anions. Described membrane electrode can be used in analytical measurements by direct potentiometry as well in potentiometric titration.</p

Electroanalytical Determination of Cysteine Using the Electrodes Based on Ternary Silver-Copper Sulfides

The amperometric determination of cysteine, using an electrode based on ternary silver-copper sulfide, is presented. Electrochemical characterizations (using cyclic voltammetry) of three electrode materials revealed that the electrode based on the material that consists of jalpaite (Ag3CuS2), doped with a small amount of metallic silver, has the best electrocatalytical performance for cysteine oxidation. For the amperometric determination, 0.142 V at pH 5 and 0.04 V at pH 7 vs. Ag/AgCl, related to the electrocatalytical oxidation of thiol group, were chosen. Electrochemical impedance spectroscopy together with Fourier transform infrared spectroscopy (FTIR) revealed that oxidation takes place on the electrode surface with fouling effect, which does not affect a wide linear working range between 1 &#956;M and 100 &#956;M. Sensitivities, at pH 5 and pH 7, are calculated to be 0.11 &#956;A &#956;M&#8722;1 and 0.10 &#956;A &#956;M&#8722;1, respectively. The detection limits were determined to be 0.036 &#956;M and 0.024 &#956;M for pH 5 and pH 7, respectively. In the presence of uric acid, folic acid, ascorbic acid, and glucose no interference was noticed. This electrode showed remarkable stability and excellent reproducibility. The electrode was exploited for the determination of cysteine in a dietary supplement with the excellent recoveries

Characterization of the Air Quality in Split, Croatia Focusing Upon Fine and Coarse Particulate Matter Analysis

<div><p>The study presents statistical analysis of air quality parameters for a five-year period including PM_2.5 (particles with an aerodynamic diameter, <i>d</i>_<i>a</i> < 2.5 µm) and PM₁₀ (<i>d</i>_<i>a</i> < 10 µm) concentrations measured at three stations in Split region, along with NO, NO_x, NO₂, SO₂, and black smoke data. Average concentrations of PM_2.5 at three different stations were 28.2, 19.9, and 14.3 µg m⁻³, whereas those for PM₁₀ were 17.8, 25.8, and 15.2 µg m⁻³. Generally, high correlations between PM_2.5 and PM₁₀ (0.62 and 0.54 respectively) were determined between industrial and residential stations, while lower correlation (0.22 between PM_2.5 and PM₁₀) was observed at a station in traffic and industrial area. Contributions of different sources were determined using multivariate receptor modeling (principal component analysis and cluster analysis) and it was found that the major source of pollution was in accordance with the station position. Comparison of particle mass concentrations with those reported for different European cities indicate lower loading for PM in the Split Region.</p> </div