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    Öğe
    A Facile Strategy for Construction of Sensor for Detection of Ondansetron and Investigation of its Redox Behavior and Thermodynamic Parameters
    (Wiley-VCH Verlag, 2019) Zaabal, Moufida; Doulache, Merzak; Karadaş Bakırhan, Nurgül; Kaddour, Samia; Saidat, Boubakeur; Özkan, Sibel Ayşıl
    A sodium dodecylsulfate-doped polypyrrole (SDS-PPy) film was elaborated on glassy carbon electrode (GCE) by an electrodeposition method in phosphate buffer solution (pH 2.0) containing pyrrole (Py) and sodium dodecyl sulfate (SDS). SDS-PPy/GCE was used for the construction of sensor, which showed excellent electrochemical response for the detection of ondansetron (OND) compared to conventional PPy. The application of the square wave (SW), with the adsorptive accumulation, indicates a maximum response at 1.33 V in H2SO4 (0.5 M). The influence of experimental parameters on determination of OND is discussed. The adsorptive stripping technique showed to be more sensitive, giving responses twice as big as those of non-accumulated OND. The substantial improvement of response permits the development of an electroanalytical technique with a linear concentration in the range (1.0–80 ?M), low detection (0.09 ?M), and quantification limits (0.3 ?M), and acceptable relative standard deviations of repeatability (0.59 %), and reproducibility (1.51 %). Consequently, this electrode is promising candidate for an accurate electroanalytical determination of OND in pharmaceutical samples with high sensitivity and selectivity, good accuracy and precision. The electrooxidation of OND at SDS-PPy/GCE at various temperatures were studied by cyclic voltammetry to evaluate both the kinetic (ks and Ea) and thermodynamic (?G*, ?H* and ?S*) parameters. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Öğe
    Simple and sensitive adsorptive stripping voltammetric assay of granisetron from its dosage form by platinum nanoparticles modified electrodes
    (Elsevier B.V., 2017) Doulache, Merzak; Karadaş Bakırhan, Nurgül; Uslu, Bengi; Saidat, Boubakeur; Trari, Mohamed; Özkan, Sibel Ayşıl
    Base to the interfacial adsorptive nature of granisetron (GRN) on platinum particles modified glassy carbon electrode (PtPs/GCE). A sensitive analytical method for trace analysis of GRN based on the adsorptive stripping technique has been developed. The application of a square wave mode for the stripping of adsorbed GRN has proved to be much more sensitive compared to differential pulse scan. A study of the variation in the peak current with solution variables such as pH, concentration of granisetron, possible interference, and instrumental variables, such as accumulation time and accumulation potential, has resulted in the optimization of the oxidation signal for analytical purposes. Under the optimized conditions, the square wave peak current showed two linear ranges of GRN concentration: 0.01–0.5 ?M and 0.5–25 ?M with correlation coefficients of 0.997 and 0.998, respectively. Nanomolar detection limit was obtained as 1.95 nM for the first linear range. Possible interferences by substances usually present in the pharmaceutical formulations were also evaluated. The proposed electrochemical procedure was successfully applied for the determination of GRN in pharmaceutical injection samples (SETRON® 3 mg/3 mL) with average recovery of 100.30%. © 2017 Elsevier B.V.