Yazar "Shah, Afzal" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Carbon quantum dots co-catalyzed with multiwalled carbon nanotubes and silver nanoparticles modified nanosensor for the electrochemical assay of anti-HIV drug Rilpivirine(Elsevier B.V., 2019) Aftab, Saima; Kurbanoğlu, Sevinç; Özçelikay, Göksu; Karadaş Bakırhan, Nurgül; Shah, Afzal; Özkan, Sibel AyşılIn this study, a novel and sensitive voltammetric nanosensor has been developed for the first time, for the detection of Rilpivirine based on amine-functionalized multiwalled carbon nanotubes (NH 2 -fMWCNT) with Ag nanoparticles onto carbon quantum dots modified glassy carbon electrode. Scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were employed for characterization of the modified electrode. The Rilpivirine showed two irreversible oxidation peaks at 1.20 V and 1.42 V, at all the investigated pH values. The cyclic voltammetry results demonstrated excellent electrocatalytic activity of the modified electrode toward the oxidation of Rilpivirine as endorsed by the enhanced current responses compared to bare electrode. The electrochemical catalytic activity was further utilized as a sensitive detection method for the investigation of the redox mechanism of Rilpivirine using differential pulse voltammetry (DPV). For experimental conditions optimization the influence of supporting electrolyte and pH was examined and 0.5 M H 2 SO 4 was selected as the best electrolyte for getting intense current signals of the target analyte. The relationship of anodic peaks potentials for peak 1 and peak 2 (E P1 and E P2 ) with pH values and scan rate was also studied. Scan rate results showed that the oxidation of Rilpivirine at the nanosensor surface occurs under adsorption controlled manner. Therefore, differential pulse adsorptive stripping voltammetric technique was employed for the determination of Rilpivirine. Optimum accumulation potential and time were found as 0 V and 60 s, respectively. Under these optimum conditions, response of Rilpivirine demonstrated a linear behavior in the concentration range from 1.00 × 10 ?9 to 7.00 × 10 -9 M, with a limit of detection value of 3.00 × 10 -11 M and 6.40 × 10 -11 M for peak 1 and peak 2 in aqueous medium containing 0.5 M H 2 SO 4 as supporting electrolyte, respectively. Interferences studies were achieved in the presence of 500 fold higher concentration of interfering agents to check the selectivity of the developed method. The designed method was successfully applied for the determination of Rilpivirine in biological fluids, urine and synthetic human serum as a real sample. The value of limit of detection were found to be 1.79 × 10 -10 M, 4.47 × 10 -10 M in serum samples, 5.26 × 10 -10 M and 8.27 × 10 -10 M in urine samples for peak 1 and peak 2, respectively. Recovery experiments were carried out to check the accuracy and precision of the designed method. Moreover, the repeatability, reproducibility and stability of the modified electrode in supporting electrolyte, serum and urine samples were investigated. © 2019 Elsevier B.V.Öğe Chemical Nanosensors in Pharmaceutical Analysis(Academic Press Ltd-Elsevier Science Ltd, 2019) Kurbanoglu, Sevinc; Bakirhan, Nurgul K.; Shah, Afzal; Ozkan, Sibel A.[Abstract Not Available]Öğe Development of a Surfactant/Platinum Composite for Sensitive Cardio-selective Beta Blocker Detection and their Theoretical Studies(Wiley-V C H Verlag Gmbh, 2019) Zahid, Anum; Bakirhan, Nurgul K.; Karadurmus, Leyla; Shah, Afzal; Ozkan, Sibel A.An electrooxidative behavior of beta-blocker drug esmolol was thoroughly investigated by using glassy carbon electrode modified with sodium dodecyl sulfate-based platinum nanoparticles. The designed nanosensor exhibited remarkable electro-catalytic effect by dramatically boosting the signal of the esmolol as compared to the bare electrode with detection limit up to picomolar. The effects of pH, scan rate, temperature, deposition potential, deposition time, effect of electrolyte and interfering agents were investigated to optimize conditions for getting intense signal of the analyte. Under optimized experimental conditions, a linear calibration plot for esmolol with a detection limit of 60 pM was obtained. The analyte sensing ability of the modified electrode was supported by the application of theoretical studies that showed favorable interaction between sodium dodecyl sulfate/platinum nanoparticles composite and esmolol. In this study, our aim was to developed a nanosensor for the sensitive detection of esmolol by electrochemical assay. We tried a lot of different modification style and modifiers for creating a sensitive nanosensor for esmolol. This nanosensor can be applied to the esmolol in serum sample without using any further separation, evaporation or precipitation steps. Application could apply in serum sample to test accuracy of our sensor and method. The high recovery results were observed in serum study.Öğe Noble Metal Nanoparticles in Electrochemical Analysis of Drugs(Academic Press Ltd-Elsevier Science Ltd, 2019) Bakirhan, Nurgul K.; Shah, Afzal; Ozkan, Sibel A.[Abstract Not Available]Öğe Optical Nanosensors for Pharmaceutical Detection(Academic Press Ltd-Elsevier Science Ltd, 2019) Nosheen, Erum; Shah, Afzal; Iftikhar, Faiza Jan; Aftab, Saima; Bakirhan, Nurgul K.; Ozkan, Sibel A.[Abstract Not Available]
