Browsing by Author "Fitoz, Alper"

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    Bazı ksantin türevlerinin modifiye kalem grafit elektrotta elektrokimyasal tayini ve DNA ile etkileşimleri
    (Fen Bilimleri Enstitüsü, 2021) Fitoz, Alper; Yazan, Zehra; Kimya
    In this study, a new electrochemical platform was produced for simultaneous electrochemical analysis of xanthine and its two N-methyl derivatives theophylline and theobromine. The surface of the electrochemical platform was characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques, while its performance was examined using cyclic voltammetry and electrochemical impedance spectroscopy techniques. The electrochemical behaviors of xanthine and two N-methyl derivatives on the surface of the electrochemical platform were investigated by cyclic voltammetry and differential pulse voltammetry techniques. The novel electrochemical platform developed with NiO, multi-walled carbon nanotube, and natural clay material was used for the simultaneous determination of xanthine, theophylline and theobromine together with the differential pulse method. The changes in the anodic peak currents and potentials of xanthine, theophylline, and theobromine with the pH change of the supporting electrolyte were examined. The developed simultaneous analysis method was questioned with selectivity, real sample studies, and interference studies on three different matrices. In addition, the DNA interaction of these three analytes was investigated on the developed electrochemical platform. For all three analytes, the interaction with DNA was determined to be thermodynamically spontaneous. The electrolyte effect and the pH effect of the selected electrolyte and its behavior on the bare pencil graphite electrode surface were investigated using cyclic voltammetry, differential pulse, and square wave voltammetry techniques for the caffeine molecule that was not used in the simultaneous analysis. An analysis method was developed for the differential pulse and the square wave voltammetry techniques under the determined optimum conditions, and the developed methods were tested with real sample and interference studies. The two developed methods effectively performed real sample analyzes. In addition, DNA interaction was examined with these two techniques, and it was revealed that the binding of caffeine to DNA is thermodynamically spontaneous also DNA interactions were accomplished with the help of weak electrostatic forces for all studied analytes.