Ali Osman SOLAK

Article | 2013 | Sensors and Actuators B: Chemical188

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 immobilizing DNA probes and sensing DNA hyb . . .ridization. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), and found that the charge transfer resistance (Rct) of the electrode increased with the concentration of the target DNA hybridized with the ss-DNA. The linear detection range was from 1.0 × 10−13 M to 1.0 × 10−7 M and the detection limit was 1.10 × 10−14 M (n = 6). Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability, and high sensitivity. - Keywords: Graphene oxide; Gold nanoparticles; Electrochemical impedance spectroscopy; DNA nanobiosenso More less

Ali Osman SOLAK

Article | 2011 | Journal of Computational and Theoretical Nanoscience8 ( 10 )

This paper presents the Pseudo phase plane (PPP) method for detecting the existence of a nanofilm on the nitroazobenzene-modified glassy carbon electrode (NAB-GC) system. This modified electrode systems and nitroazobenze-nanofilm were prepared by the electrochemical reduction of diazonium salt of NAB at the glassy carbon electrodes (GCE) in nonaqueous media. The IR spectra of the bare glassy carbon electrodes (GCE), the NAB-GC electrode system and the organic NAB film were recorded. The IR data of the bare GC, NAB-GC and NAB film were categorized into five series consisting of FILM1, GC-NAB1, GC1; FILM2, GC-NAB2, GC2; FILM3, GC-NAB3 . . ., GC3 and FILM4, GC-NAB4, GC4 respectively. The PPP approach was applied to each group of the data of unmodified and modified electrode systems with nanofilm. The results provided by PPP method show the existence of the NAB film on the modified GC electrode. - Keywords: CORRELATION; MODIFIED GLASSY CARBON ELECTRODE; MUTUAL INFORMATION; NANO-FILM; NANOANALYSIS; PSEUDO PHASE PLANE METHO More less

Ali Osman SOLAK

Article | 2011 | Instrumentation Science & Technology39 ( 2 )

Benzo[c]cinnoline (BCC) molecules were electrochemically grafted onto a glassy carbon (GC) surface in nonaqueous media, and the modified surface was characterized using cyclic voltammetry (CV) with redox probes. Blockage of the electron transfer on the modified surface was observed using redox probes. Electrocatalytic effect of 2BCC modified GC (2BCC-GC) electrode surface towards to the electrochemical reduction of dioxygen was also investigated. A mechanistic scheme for the electrochemical catalysis was proposed. To clarify the mechanism of the dioxygen reduction, a less basic film of 2-benzo[c]cinnoline 6-oxide (2BCCNO) molecules . . .was also prepared at the glassy carbon surface. The effect of electrochemical catalysis of dioxygen reduction at the 2BCC-GC surface was compared to that at the 2BCCNO-GC surface. - Keywords: 2-benzo[c]cinnoline modified electrode, benzo[c]cinnoline, cyclic voltammetry electrocatalytic dioxygen reduction, electrochemical modificatio More less

Ali Osman SOLAK

Article | 2012 | Journal of Inclusion Phenomena and Macrocyclic Chemistry74 ( 1 )

A new calix[4]pyrrole functionalized vic-dioxime, 3-(4-methyl-9,9,14,14,19,19-hexaethylcalix[4]pyrrole)benzoaminoglyoxime (LH2) was synthesized from anti-chloroglyoxime and 3-aminophenyl-calix[4]pyrrole at room temperature. The mononuclear complexes {nickel(II), copper(II) and cobalt(II)} of this vic-dioxime ligand were prepared and their structures were confirmed by elemental analysis, IR and UV–Vis spectrophotometry, magnetic susceptibility; the MS, 1H and 13C NMR spectra of the LH2 ligand and its Ni(II) complex were also recorded. The experimental results indicated that the ligand:metal ratio was 2:1 in the cases of Ni(II), Cu(II . . .) and Co(II) complexes as is with most vic-dioximes. Electrochemical properties of the ligand, and its complexes were investigated in DMSO solution by cyclic voltammetry at 200 mV s−1 scan rate. - Keywords: Oxime vic-Dioxime Transition metal complex Calix[4]pyrrole Cyclic voltammetry More less

Ali Osman SOLAK

Article | 2012 | Sensors and Actuators B: Chemical171-172

This study reports the electrochemical modification of glassy carbon (GC) surface with etodolac (ETO), the characterization of this ETO modified glassy carbon (ETO/GC) electrode and its electroanalytical application for the determination of Pb(II) ions. Binding type of the etodolac with the glassy carbon surface was investigated and found that it was through the etheric linkage revealed from the reflection–absorption infrared spectroscopy (RAIRS). The ETO/GC electrode was characterized by cyclic voltammetry (CV), reflection–adsorption IR spectroscopy, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XP . . .S) and atomic force microscopy (AFM). The ETO/GC electrode was found to be suitable for selective determination of Pb(II) by adsorptive stripping voltammetry in the solutions of the mixture of heavy metal ions, such as Cu(II) and Cd(II) and showed high stability and reproducibility. The stability and the potential range of the ETO/GC electrode were also studied. The developed method was validated according to the ICH guideline and found to be linear, sensitive, selective, precise and accurate. The linearity range of Pb(II) was 5.0 × 10−10 to 1.0 × 10−8 M with the detection limit (S/N = 3) of 1.67 × 10−10 M. The validated method was applied successfully for the determination of Pb(II) in real samples. - Keywords: Etodolac; Characterization; Glassy carbon electrode; Electrochemical sensor; Pb(II) ion detection; Adsorptive stripping voltammetr More less

Ali Osman SOLAK

Article | 2023 | Iranian Journal of Chemistry and Chemical Engineering (IJCCE)42 ( 5 )

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 via the “Taguchi Method”. In the trials, . . . flash calcination temperature (500, 600, 700, 800 °C), reaction temperature (50, 60, 70, 80 °C), solid-liquid ratio (0.15, 0.20, 0.25 and 0.30 g/mL), grain size (-500355,-355212,-212150, and-150 µm), and reaction time (15, 30, 45, and 60 minutes) were selected as the parameters and velocity of gas flow and mixing speed were considered as constant in all the experiments. In addition, experiments were carried out at atmospheric pressure. Accordingly, optimum conditions were found as flash calcination temperature of 500°C, reaction temperature of 50°C, grain size of-212150 µm, solid-liquid ratio of 0.30 g/m, and reaction time of 60 minutes. The estimated dissolution under these conditions was 99.47 and dissolution of 100 was obtained in the experiments conducted. The aim of the study was to obtain more economical and high-purity boric acid compared to sulfuric acid via an environmentally friendly process without any waste. Keywords: boric acid; calcined colemanite; flash calcination; optimization; sulfur dioxid More less

Ali Osman SOLAK

Article | 2012 | Surface and Interface Analysis44 ( 2 )

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 revealed that calix[4]pyrrole was bonded . . .to the glassy carbon surface via the etheric linkage. The stability of the modified GC electrode was also studied. Copyright © 2011 John Wiley & Sons, Ltd More less

Ali Osman SOLAK

Article | 2011 | Spectroscopy Letters: An International Journal for Rapid Communication 44 ( 3 )

Present work aims to create a benzoylglycine (BG)-modified glassy carbon (GC) substrate exploiting the electroreduction of diazonium salts. Dopamine was used to confirm the attachment of benzoylglycine molecules onto the glassy carbon surface by observing the blockage of the electron transfer using cyclic voltammetry (CV). BG-modified GC surface (BG-GC) was also characterized by Raman spectroscopy and electrochemical impedance spectroscopy (EIS) techniques. The ellipsometric thickness of the BG film was measured as approximately 14 nm for seven CV cycles. The electrocatalytic effect of BG-GC electrode surface against dioxygen reduct . . .ion was investigated. The catalytic effect for dioxygen reduction of the BG-GC surface was compared with that of 2-benzo[c]cinnoline, 2-benzo[c]cinnoline 6-oxide- and diethylene glycol bis(2-aminophenyl)ether-modified GC surfaces to clarify the mechanism of catalysis of the surfaces in terms of molecular structure. - KEYWORDS: benzoylglycine modification, dioxygen reduction, electrocatalytic effect, electrochemical impedance spectroscopy, Raman spectroscop More less

Ali Osman SOLAK

Article | 2011 | Polyhedron3 ( 10 )

This paper presents a new azacrown containing vic-dioxime; anti-N-(4-aminophenyl)aza-15-crown-5-glyoxime (LH2), and its mononuclear nickel(II), copper(II), cobalt(II), cadmium(II) and zinc(II) complexes. The azacrown moieties appended at the periphery of the oxime provide solubility for the vic-dioxime ligand and complexes in common organic solvents. The mononuclear M(LH)2 (M = Ni and Cu), M(LH)2(H2O)2 (M = Co) and [M(LH)(H2O)(Cl)] (M = Cd and Zn) complexes have been obtained with the metal:ligand ratios of 1:2 and 1:1. The structure of the ligand is confirmed by elemental analysis, Fourier transform infrared (FT-IR), ultraviolet–vi . . .sible (UV–Vis), mass spectrometry (MS), one-dimensional (1D) 1H, 13C NMR, distortionless enhancement by polarization transfer (DEPT) and two-dimensional (2D) heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) techniques. The structures of the complexes are confirmed by elemental analyses, MS, UV–Vis, FT-IR and 1H, 13C NMR techniques. Redox behaviors of the ligand and its complexes have been investigated by cyclic voltammetry at the glassy carbon electrode in 0.1 M TBATFB in DMSO. The antibacterial activity was studied against Staphylococcus aureus ATCC 29213, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Lactobacillus acidophilus RSHM 06029, Escherichia coli ATCC 25922, Pseudomonasaeruginosa ATCC 27853. The antimicrobial test results indicate that all the complexes have low levels of antibacterial activity against both Gram negative and Gram positive bacterial species. - Keywords: vic-Dioxime; Azacrown ether; Macrocyclic ligand; Metal complexes; Cyclic voltammetry; Antimicrobial activit More less

Ali Osman SOLAK

Article | 2014 | Sensor Letters12 ( 11 )

The voltammetric behavior of sildenafil citrate (SC) was studied through differential pulse stripping voltammetry. The best sensitivity, optimal experimental conditions and settings for the voltammetric method development were obtained by applying experimental design and optimization methodology to the designed sample runs at different accumulation times, accumulation potentials and pHs. The linearity over the concentration range 1 × 10–7 M–8 × 10–6 M for SC was determined and the limit of detection (LOD) was 3.1 × 10–8 M. For the method ability and validity, mean recovery result and relative standard deviation were found to be 99.3 . . .% and 2.19%, respectively. The method was applied to the determination of SC in pharmaceutical and plasma samples. More less

Ali Osman SOLAK

Article | 2012 | Chemical Papers66 ( 12 )

Acidity constant values of benzoic acid (BA)-modified platinum electrode (Pt-BA) and p-aminobenzoic acid (pABA)-modified platinum electrode (Pt-NHBA) surfaces were determined using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and contact angle measurements (CAM). Diazonium tetrafluoroborate salt reduction and pABA oxidation reactions were used to prepare (Pt-BA) and (Pt-NHBA) surfaces, respectively. Both surfaces exhibited pH dependence with [Fe(CN)6]3−/4− redox probe solutions at different pH; this allowed us to estimate the surface pK a values. Acidity constants for Pt-BA surface were found to be pK a (3. . . .09 ± 0.25), (4.89 ± 0.11), and (3.91 ± 0.54) by CV, EIS, and CAM techniques, respectively, while the values for Pt-NHBA surface were pK a (3.16 ± 0.45), (4.24 ± 0.40), and (5.64 ± 0.12). The Pt-BA surface pK a values were lower in CV and CAM measurements relative to the bulk solution of BA, while a higher value was observed in EIS for Pt-BA surface. The pK a values determined for Pt-NHBA surface via both CV and EIS were lower than the bulk value; however, the result obtained from CAM was one unit higher than pK a of bulk pABA. - Keywords: platinum electrode p-aminobenzoic acid cyclic voltammetry electrochemical impedance spectroscopy determination of pK a contact angl More less

Ali Osman SOLAK

Article | 2020 | Inorganic Chemistry Communications116

Electrochemical and spectroelectrochemical properties of newly synthesized diazonium salt of 2-(2-(1,3-dioxo- 3,3a-dihydro-1H-isoindol-2(7aH)-yl)-1-(3 methyl-3-phenylcyclobutyl)ethylidene) hydrazinecarboxamide (DDPHC-DAS) were studied using glassy carbon (GC) electrode. In the current study, surface characterization was performed by cyclic voltammetry (CV). Besides electrochemical impedance spectroscopy (EIS) was used for the electrochemical and spectroelectrochemical characterization. Surface images were obtained using scanning electron microscopy (SEM). After completion of modification and characterization process, DDPHC-DAS surfa . . .ce was examined for the usability for the quantitative determination of phenol and chlorophenol derivatives by using CV, square wave voltammetry (SWV) and differential pulse voltammetry (DPV). Phenol and chlorophenol solutions that were prepared in Britton-Robinson (BR) buffer solution (pH 8-12) were employed in this research. The presented study proves that all of compounds can be quantitatively determined not only simultaneously but also independently More less