Partial cation substitution can significantly change the physical properties of parent compounds. By controlling the chemical composition and knowing the mutual relationship between composition and physical properties, it is possible to tailor the properties of materials to those that are superior for desired technological application. Using the polyol synthesis procedure, a series of yttrium-substituted iron oxide nanoconstructs, γ-FeYO (YIONs), was prepared.
View Article and Find Full Text PDFIn this work, we investigated the morphological and electrochemical properties of gallium/bismuth mixed oxide. The bismuth concentration was varied from 0 to 100%. The correct ratio was determined with inductively coupled plasma-optical emission spectroscopy (ICP-OES), while surface characteristics were determined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurement.
View Article and Find Full Text PDFStable, water-soluble titanium complexed with mandelic acid was used as a precursor for titanium phosphorus double oxide obtained in hydrothermal conditions in the presence of phosphoric acid. Surprisingly, hydrolysis of organic complexes provided a microstructured sphere with narrow size distribution, low aggregation and a small fraction of morphological irregularities. Obtained microspheres had a complex structure comprised of flakes, whose size could be manipulated with temperature conditions.
View Article and Find Full Text PDFMorphine (MORPH) is natural alkaloid and mainly used as a pain reliever. Its monitoring in human body fluids is crucial for modern medicine. In this paper, we have developed an electrochemical sensor for submicromolar detection of MORPH.
View Article and Find Full Text PDFType of the wood used for the aging highly influences the quality of alcoholic beverages. In this research we explored the potential of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) to establish fingerprints characteristic for each wood and to enable determining the type of the wood used in the aging process. Eleven different wood samples were used to prepare three different types of spirits during 15 months.
View Article and Find Full Text PDFChlorine dioxide (ClO) degradation of the organophosphorus pesticides azamethiphos (AZA) and dimethoate (DM) (10 mg/L) in deionized water and in Sava River water was investigated for the first time. Pesticide degradation was studied in terms of ClO level (5 and 10 mg/L), degradation duration (0.5, 1, 2, 3, 6, and 24 h), pH (3.
View Article and Find Full Text PDFUpon release in response to stress, epinephrine (Epi) may interact with labile iron pool in human plasma with potentially important (patho)physiological consequences. We have shown that Epi and Fe build stable 1:1 high-spin bidentate complex at physiological pH, and that Epi does not undergo degradation in the presence of iron. However, the interactions of Epi with the more soluble Fe, and the impact of iron on biological activity of Epi are still not known.
View Article and Find Full Text PDFHerein we report effects of partial substitution of Fe by Y in magnetite (FeO) on morphology and inorganic arsenic species adsorption efficiency of the Fe Y O nanoparticles formed. The series of Fe Y O (x = 0.00, 0.
View Article and Find Full Text PDFAn electrochemical sensor is described for the determination of L-dopa (levodopa; 3,4-dihydroxyphenylalanine). An inkjet-printed carbon nanotube (IJPCNT) electrode was modified with manganese dioxide microspheres by drop-casting. They coating was characterized by field emission scanning electron microscopy, Fourier-transform infrared spectroscopy and X-ray powder diffraction.
View Article and Find Full Text PDFFive novel silver(I) complexes with 4,7-phenanthroline (4,7-phen), [Ag(NO-O)(4,7-phen-μ-N4,N7)] (1), [Ag(ClO-О)(4,7-phen-μ-N4,N7)] (2), [Ag(CFCOO-O)(4,7-phen-μ-N4,N7)] (3), [Ag(HO)(4,7-phen)](SbF) (4) and {[Ag(HO)(4,7-phen-μ-N4,N7)](BF)} (5) were synthesized, structurally elucidated and biologically evaluated. These complexes showed selectivity towards Candida spp. in comparison to the tested bacteria and effectively inhibited the growth of four different Candida species, particularly of C.
View Article and Find Full Text PDFA series of MgFeO₄ ( ═ 0-1) nanoparticles was synthesized in order to prepare novel MgFeO₄/glassy carbon modified electrodes. Effects of magnesium content () on the analytical performance of the modified electrodes in the detection of gallic acid were evaluated. It was found that magnesium concentration and crystallite/particle size of the prepared nanoparticles play significant roles in the sensing properties of modified electrodes.
View Article and Find Full Text PDFBiliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy, 1H NMR, EPR, fluorimetry, and electrochemical methods.
View Article and Find Full Text PDFAn increase in the copper pool in body fluids has been related to a number of pathological conditions, including infections. Copper ions may affect antibiotics via the formation of coordination bonds and/or redox reactions. Herein, we analyzed the interactions of Cu with eight β-lactam antibiotics using UV-Vis spectrophotometry, EPR spectroscopy, and electrochemical methods.
View Article and Find Full Text PDFThe aim of this study was to establish correlation of chemical composition and antioxidant activity of bilberry plants from Montenegro. Total phenolic, tannin, flavonoid, procyanidin and anthocyanin contents were determined in fruits and leaves extracts using spectrophotometric methods, while the measurements of metal content was carried out in an Inductively Coupled Atomic Emission Spectrometer. Qualitative and quantitative analyses of major phenolics were achieved by HPLC.
View Article and Find Full Text PDFIn this work, we aimed to propose a newly synthesized composite material with enhanced electrocatalytic properties as a novel screen-printed sensor for the quantification of NADH. Additionally, the surface was modified with alcohol dehydrogenase for the preparation of an amperometric biosensor for analysis of ethanol. Synthesized material was characterized using several microstructural (FE-SEM, HR-TEM, XRD) and electrochemical (CV, EIS) techniques.
View Article and Find Full Text PDFCoordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex.
View Article and Find Full Text PDFToxic effects of unconjugated bilirubin (BR) in neonatal hyperbilirubinemia have been related to redox and/or coordinate interactions with Cu. However, the development and mechanisms of such interactions at physiological pH have not been resolved. This study shows that BR reduces Cu to Cu in 1:1 stoichiometry.
View Article and Find Full Text PDFIn the present paper, the electrochemical behavior and the properties of two modified glassy carbon (GC) electrodes used for quantification of gallic acid in sweet wines were compared. A comparative study was conducted between titanium nitride- or wolfram carbide-doped reduced graphene oxide, labeled as TNrGO and WCrGO, respectively, modified GC electrodes, which are promising composite nanomaterials for electroanalytical applications. For the first time, WCrGO was synthesized and its electroanalytical properties compared with those of TNrGO.
View Article and Find Full Text PDFThe overall aim of this paper was to compare the multielement composition and antioxidant capacity of two Montenegrin Merlot wines obtained from specific vine clones (VCR1 and VCR 101) along with commercial Merlot wine throughout the consecutive vintages in 2010 and 2011. Elemental composition was analysed using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Additionally, antioxidant capacity was assessed by cyclic voltammetry.
View Article and Find Full Text PDFThis work presents the simultaneous determination of catechol (CC) and hydroquinone (HQ), employing a modified carbon paste electrode (CPE) with ferrite nanomaterial. Ferrite nanomaterial was doped with different amount of cobalt and this was investigated toward simultaneous oxidation of CC and HQ. It was shown that this modification strongly increases electrochemical characteristics of the CPE.
View Article and Find Full Text PDFA boron doped diamond (BDD) electrode was investigated for use as an electrochemical sensor for α-lipoic acid (LA) using amperometric and differential pulse voltammetric detection. LA displays a well expressed oxidation peak at +0.9 V vs.
View Article and Find Full Text PDFIn this work new designed, highly sensitive electrochemical method is developed for the determination of nitrites in tap water using glassy carbon electrode modified with graphene nanoribbons (GNs/GCE). Graphene nanoribbons (GNs) have been newly synthetized and aligned to the surface of glassy carbon electrode (GCE) and exhibited excellent electrocatalytic activity for nitrite oxidation with a very high peak currents. Studies about electrochemical behavior and optimization of the most important experimental conditions were done using cyclic voltammetry (CV), while quantitative studies were done with amperometric detection.
View Article and Find Full Text PDFThis work presents the electrochemical behavior of levodopa (L-DOPA), at boron-doped diamond (BDD) electrodes, using cycling voltammetry (CV), in Britton-Robinson (BR) buffer solution, and application of the proposed electrode for the determination of L-DOPA in extracts from the seeds of velvet bean (Mucuna prurita Hook or Mucuna pruriens (L.) DC.).
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