Carbon-Based Composite Materials for Electrodes

Carbon-Based Composite Materials for Electrodes is a new open Special Issue of Materials, which has the goal of publishing original research and review articles focused on carbon nanotubes, graphene, activated carbon, graphite, pencil graphite, graphene oxide, graphene nanoplatelets, pyrolytic graphite, organic mass derived carbon, fullerenes, diamond, glassy carbon, carbon fibers, and other composites for electrode preparation and its applications [...

Simultaneous determination of paracetamol, dextromethorphan, chlorpheniramine, pseudoephedrine and major impurities of paracetamol and pseudoephedrine by using capillary electrophoresis

A capillary electrophoresis method was developed for the first time and optimized for thedetermination of paracetamol, pseudoephedrine, dextromethorphan, chlorpheniramine,4-aminophenol and ephedrine in tablet formulation. Optimum electrophoretic conditions wereachieved by using a background electrolyte of 75 mmol L-1 sodium borate buffer at pH 8.0, acapillary temperature of 30°C, a separation voltage of 30 kV and a pressure injection of the sampleat 50 mbar for 10 s. Calibration graphs showed a good linearity with a coefficient of determination(R2) of at least 0.999 for all compounds. Intraday and interday precision (expressed as relativestandard deviation (RSD) %) were lower than 1.39% for capillary electrophoresis method. Thedeveloped method was demonstrated to be simple and rapid for the determination of paracetamol,pseudoephedrine, dextromethorphan, chlorpheniramine, 4-aminophenol and ephedrine in tabletformulation providing recoveries in the range between 99.62 and 100.57% for all analytes

Electrooxidation of physostigmine at different electrodes

824-829The elcctrooxidation of physostigmine (PHY) has been investigated at different pH values at platinum, ruthenium, carbon paste and glassy carbon electrodes. It has been found that Ru and Pt electrodes played an important role in the oxidation. The nature of the curves are strongly dependent upon the scan rate, supporting electrolyte and the pH values of the solutions. With glassy carbon electrode, the results are highly dependent upon the activation process of the  electrode. Activated glassy carbon and oxidized Pt and Ru electrodes give the best results. Suitable mechanisms for oxidation of PHY in both acidic and basic media have been proposed

An Efficient, Simultaneous Electrochemical Assay of Rosuvastatin and Ezetimibe from Human Urine and Serum Samples

The drug combination of rosuvastatin (ROS) and ezetimibe (EZE) is used to treat hypercholesterolemia. In this work, a simultaneous electrochemical examination of ROS and EZE was conducted for the first time. The electrochemical determination of ROS and EZE was carried out using adsorptive stripping differential pulse voltammetry (AdSDPV) on a glassy carbon electrode (GCE) in 0.1 M H2SO4. The effects of the pH, scan rate, deposition potential, and time on the detection of ROS and EZE were analyzed. Under optimum conditions, the developed sensor exhibited a linear response between 1.0 × 10−6 M and 2.5 × 10−5 M for EZE and 5.0 × 10−6 M, and 1.25 × 10−5 M for ROS. The detection limits for ROS and EZE were 3.0 × 10−7 M and 2.0 × 10−6 M, respectively. The developed sensor was validated in terms of linear range, accuracy, precision, the limit of determination (LOD), and the limit of quantification (LOQ), and it was evaluated according to ICH Guidelines and USP criteria. The proposed method was also used to determine ROS and EZE in human urine and serum samples, which are reported in terms of recovery studies

Differential Pulse Voltammetric Determination of Fulvestrant in Pharmaceutical Dosage Forms and Serum Samples

The electrooxidation behavior and determination of fulvestrant at a glassy carbon electrode were investigated. The voltammetric study of the model compounds allowed elucidating the possible oxidation mechanism of fulvestrant. The dependence of the peak current and peak potentials on pH, concentration, nature of the buffer, and scan rate was determined. The oxidation of fulvestrant showed a single and irreversible peak at glassy carbon electrode, and the process was found diffusion controlled. Linear responses were obtained for the concentrations between 4×10−6 M and 6×10−5 M in standard samples and between 2×10−5 M and 1×10−4 M in serum samples. The repeatability of the method was found 0.93 RSD%. The repeatability, reproducibility, precision, and accuracy of proposed method were investigated

İletken polimerlerin elektrokimyasal sentezi ve modifiye elektrod olarak kullanımı

TÜBİTAK TBAG15.11.1996Bu proje kapsamında bazı iletken polimerler ve polimer kompozitlen elde edilmiştir- İletken polimerlerin sentezinde kimyasal yöntemlerin yanında özellikle elektrokimyasal yöntemler de kullanılmıştır. Elde edilen tüm ürünler element analizi, FTIR, difransıyel taramalı kalorimetre (DSC), termal gravimetrik analiz (TGA), taramalı elektron mıkroskopisı (SEM) gibi yöntemlerle karakterize edilmiştir.Poli(N-vinilimidazol) (PVI) elektrokimyasal yöntemle sentezlenmiş ve destek elektrolitin yükleyici etkisinden dolayı ilerken bir materyal olarak elde edilmiştir. Yalıtkan bir polimer olan PVTnın, iletken bir polimer olan polipirol ile çeşitli bileşimlerde iletken kompozitleri elektrokimyasal yöntemle elde edilmiştir.Kimyasal yöntemle elde edilen PVFün yapısı, iyotla reaksiyona girdirilerek değiştirilmiştir. Bu yöntemle yükleyici iyodun polimerle daha kararlı bir yük-transfer kompleksi oluşturduğu görülmüş ve daha kararlı bir iletkenlik elde edilmiştir. Cis-l-4-Polibütadien (PB), $I_2$ yükleme yoluyla iletken bir materyal olarak elde edilmiştir. PB ve Ppy iletken kompozitleri de elektrokimyasal yöntemle sentez edilmiş ve çeşitli yöntemlerle karakterize edilmiştir.Bu polimerik materyallerin iletkenliklerinin sıcaklıkla değişimi "Mott Değişken Aralıklı Atlama" teorisine uymaktadır. Poli(7-vinilimidazol)'ün karbon- pasta elektroda eklenmesi ile polimer modifiye elektrod elde edilmiştir. Bu polimer elektrod, Irnipirarnin bidroklorür ve amitriptilin hidroklorür'ün voltametrik tayininde kullanılmıştır. Polimer-modİfiye elektrodla daha hassas sonuçlar elde edilmiştir

09 Altun.qxp

Abstract The electrochemical behavior and determination of nabumetone, nonsteroidal anti-inflammatory drug, were studied in aqueous alcohol medium at a glassy carbon electrode using cyclic, differential pulse (DP) and osteryoung square wave (OSW) voltammetric techniques. In pH 3.7 acetate buffer, nabumetone solution presents a well-defined anodic response at 1.2 V as shown by the proposed methods. The anodic peak was characterized as being irreversible and diffusioncontrolled. The slope of the log ip -log v linear plot was 0.52 indicating the diffusion control for pH 3.7 acetate buffer solution. Under optimal conditions, a detection limit of 7.65 × 10 -8 M for DPV and 3.60 × 10 -8 M for OSW, and a linear calibration graph in the range from 1 × 10 -6 M to 8 × 10 -5 M were obtained for both methods. The procedure was successfully applied to the determination of the drug in tablets, spiked human serum and spiked human urine with good recoveries. The detection limits were 2.31 × 10 -7 M and 2.53 × 10 -7 M in human serum and 2.68 × 10 -7 M and 2.51 × 10 -7 M in human urine for DPV and OSWV method, respectively