Turkey has the largest boron reserves in the world with a rate of approximately 72. The most common commercial boron reserves in Turkey are colemanite, tincal, and ulexite. Boric acid, which is the most commonly used boron compound in Turkey, is obtained from the dissolution of colemanite with sulfuric acid. In the present study, an aqueous medium saturated with sulfur dioxide instead of sulfuric acid was used in order to obtain boric acid. Colemanite ore was flash calcined at various temperatures and optimum dissolution conditions of the ore obtained in water saturated with SO2 were examined ...Daha fazlası
In this study, 4-thiophenol modified glassy carbon electrode was prepared by the reduction of 4-diazothiophenol tetrafluoroborate salt. Silver nanoparticles were attached to the thiophenol modified surface to prepare a thiophenol-silver nanoparticle composite film. 4-Aminothiopenol molecules were deposited by self-assembling technique to form multi-layered nanofilms of TP/SNP/PhNH2 on glassy carbon substrate. These surfaces were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, reflectance-absorption infrared spectroscopy, and ellips ...Daha fazlası
A single compartment biofuel cell (BFC) based on an anode and a cathode powered by the same fuel glucose is reported. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose consuming biocatalyst for both anode and cathode of the BFC. The 5-amino-1,10-phenanthroline modified graphite rod electrode (GRE) with cross-linked GOx was used as the bioanode, and the GRE with co-immobilised horseradish peroxidase and GOx was exploited as the biocathode of the BFC. The open-circuit voltage of the designed BFC exceeded 450 mV and a maximal power density of 3.5 µW/cm2 was registered at a cel ...Daha fazlası
Sulfisoxazole (SO) was grafted to glassy carbon electrode (GCE) via the electrochemical oxidation of SO in acetonitrile solution containing 0.1 M tetrabutylammoniumtetra-fluoroborate (TBATFB). The prepared electrode was characterized by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), reflection–absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). The ellipsometric thickness of SO nanofilm at the glassy carbon surface was obtained as 14.48 ± 0.11 nm. The stability of the SO modified GCE was studied. The SO modified GCE was also utiliz ...Daha fazlası
In this study, gold nanoparticles (AuNPs) with the diameters of maximum 25 nm were self-assembled onto the surfaces of p-aminothiophenol functionalized graphene oxide (ATPGO) sheets simply by mixing their aqueous dispersions. The prepared graphene oxide (GO), ATPGO and AuNPs–ATPGO composites were characterized by a transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), reflection–absorption infrared spectroscopy (RAIRS), the X-ray diffraction (XRD) method and Raman spectroscopy. The electrochemical determination of quercetin (QR) has been studied using square wave volt ...Daha fazlası
2,4-dinitrophenol (DNP) was covalently bonded to glassy carbon substrate by cyclic voltammetry (CV) technique. 2, 4-diaminophenol film (DAPO) was acquired with electrochemical reduction of 2,4-dinitrophenol film (DNPO). Prepared films were characterized by X-ray photoelectron spectroscopy (XPS) and germanium attenuated total reflection infrared (GATR-FT-IR) spectroscopy. A hemispherical germanium ATR element used with p-polarized light at 65° incidence angle yielded high signal/noise IR spectra for monolayer coverage of molecules on glassy carbon substrate. Layer thickness of films was measure ...Daha fazlası
Graphene oxide (GO) based glassy carbon (GC) electrode has been prepared. Firstly, p-nitrophenyl (NP) modified GC (NP/GC) electrode was prepared via the electrochemical reduction of its tetraflouroborate diazonium salt. After the formation of NP/GC electrode, the negative potential was applied to NP/GC electrode to reduce the nitro groups to amine. p-Aminophenyl (AP) modified GC (AP/GC) electrode was immersed into a graphene oxide solution containing 1-ethyl-3(3-(dimethlyamino)propyl)-carbodiimide. Hence, we constructed GO terminated AP modified GC (GO/AP/GC) electrode. NP/GC, AP/GC and GO/AP/ ...Daha fazlası
A highly sensitive method for detection of DNA hybridization was developed. This method was based on the modification of glassy carbon electrode with gold nanoparticles (AuNPs) involving p-aminothiophenol (ATP) functionalized graphene oxide (GO). This GO was used as a platform for impedimetric genosensing using 5′-TA GGG CCA CTT GGA CCT-(CH2)3-SH-3′ single-stranded probe (ss-DNA), 5′-AGG TCC AAG TGG CCC TA-3′ (target DNA), 5′-SH-C6-TAG GGC CA-3′ (non-complementary-1) and 5′-SH-C6-TGC CCG TTA CG 3-′ (non-complementary-2) oligonucleotide sequences. The film exhibited excellent properties for imm ...Daha fazlası
The gradually Cl replacement reactions of spirocyclic mono (1 and 2) and bisferrocenyl cyclotriphosphazenes (3–5) with the potassium salt of 4-hydroxy-3-methoxybenzaldehyde (potassium vanillinate) gave mono (1a–5a), geminal (gem-1b–5b), non-geminal (cis-1b, cis-5b and trans-2b–5b), tri (1c–5c) and tetra-substituted phosphazenes (1d–5d). Some phosphazenes have stereogenic P-center(s). The chirality of 4c was verified using chiral HPLC column. Electrochemical behaviors were influenced only by the number of ferrocene groups, but not the length of the amine chains and the substituent(s). The struc ...Daha fazlası
A nanostructured silver-aniline modified pencil electrode obtained by applying experimental design and optimization was developed for the differential pulse stripping voltammetric quantification of acetaminophen in the pharmaceutical products, tablet and syrup. The electrode development process was performed by the modification of PGE with aniline using CV procedure and the reduction of silver nanoparticle on the polyaniline modified PGE. As a result, a new electrode system consisting of a nanostructured silver-polyaniline modified pencil graphite electrode (AgNS-PA-PGE) was obtained to reach ...Daha fazlası
3-Aminophenylcalix[4]pyrrole (3APCP) was grafted to a glassy carbon (GC) surface during the electrochemical oxidation process in 0.1 M tetrabutylammoniumtetra-fluoroborate (TBATFB) containing acetonitrile solution. The presence of a surface film was confirmed electrochemically by comparing voltammograms of dopamine and ferricyanide redox probes at the bare and modified electrodes. Reflection-absorption infrared spectroscopy (RAIRS), XPS, atomic force microscopy (AFM), ellipsometry and the contact angle measurements were also employed to characterize 3APCP film on GC electrode. RAIRS analysis r ...Daha fazlası
The reaction of N-(4-aminophenyl)aza-15-crown-5 (1) with anti-chlorophenylglyoxime (2) produces a novel azacrown ether containing vic-dioxime, N-(4-aminophenyl)aza-15-crown-5-phenylglyoxime (LH_2). LH_2 reacts with Ni(II), Cu(II), Co(II), Cd(II), and Zn(II) ions to yield the mononuclear transition and nontransition metal complexes [M(LH)_2] (M = Ni and Cu), [M(LH)_2(H_2O)_2] (M = Co), and [M(LH)(H_2O)(Cl)] (M = Cd and Zn). The structural features of LH_2 were studied using several techniques including elemental analysis, Fourier transform infrared spectroscopy (FT-IR), ultraviolet visible (UV ...Daha fazlası