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 | Sensors and Actuators B: Chemical157 ( 1 )

This study reports the electrochemical modification of glassy carbon (GC) electrode surface with the electro-polymerized form of 1,10-phenanthroline monohydrate (PMH), the characterization of this polyphenanthroline modified electrode (PPMH/GC) and the electroanalytical application suitable for the determination of Cd(II) ions. The PPMH/GC electrode was characterized by cyclic voltammetry, chronoamperometry and atomic force microscopy and formation of polyphenanthroline layer grafted to surface of GC electrode was evidenced. Selectivity of PPMH/GC electrode towards heavy metal ions was investigated by square wave voltammetry. The PP . . .MH/GC electrode was found to be suitable for selective determination of Cd(II) in the solutions containing the mixture of heavy metal ions and showed high stability and reproducibility. The analytical methodology was successfully applied for monitoring the toxic metal ions in real samples. - Keywords: Surface modification; Surface characterization; Glassy carbon electrode; Electrochemical sensors; Heavy metals; Cd(II) ion detectio 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 | 2012 | Sensors and Actuators B: Chemical166-168

New sensing platform based on modified glassy carbon (GC) suitable for design of heavy metal-ion sensor is reported in this study. GC-based electrodes were electrochemically modified by poly-5-nitro-1,10-phenanthroline (poly-5NP) and poly-5-amino, 6-nitro-1,10-phenanthroline (poly-5A6NP) layers. Grafting of electrochemically formed poly-5NP and poly-5A6NP layers at the GC electrode surface was confirmed by electrochemical reduction of nitro groups into amine groups. Presence of grafted poly-5NP and poly-5A6NP layers and formation of their reduced forms on the GC electrode surface were verified by cyclic voltammetry, electrochemical . . .impedance spectroscopy, contact angle measurements, ellipsometry and X-ray photoelectron spectroscopy. The applicability of poly-5NP- and poly-5A6NP-functionalized carbon surfaces for the determination of Cu(II) ions was demonstrated by formation of complexes between GC-grafted poly-5NP and poly-5A6NP layers and Cu(II) ions. - Keywords: Phenanthroline derivatives; Surface functionalization; Electrochemical polymerization; Grafting; Functionalized carbon surface More less