Browsing by Author "Topcu, Cihan"

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Flow Injection Potentiometric Determination of Silver(I) in Photographic Film Developing Solution Samples by Polyvinylchloride Membrane Silver(I) Selective Electrode
(Chem Soc Pakistan, 2016) Topcu, Cihan; Coldur, Fatih; Andac, Muberra; Cubuk, Osman; Kanberoglu, Gulsah Saydan; Caglar, Bulent; Isildak, Ibrahim
A polyvinylchloride (PVC) membrane silver(I) selective electrode was developed for the determination of silver(I) ions in photographic film developing solutions. The electrode was embedded into a home-made flow cell and successfully used as a potentiometric detector in a flow injection potentiometric (FIP) system. Under the optimized flow injection conditions, the electrode exhibited a non-Nernstian slope of 67.20 +/- 0.80 mV in the linear range from 1.0x10(-5) to 1.0x10(-1) mol/L (R-2 = 0.9961) and the lowest value for limit of detection (LOD) was calculated as 7.1x10(-6) mol/L. The electrode displayed good sensitivity, selectivity, repeatable and rapid response towards silver(I) ions. Lifetime of the electrode was determined as at least two months in FIP system. The electrode was also successfully applied for the potentiometric determination of silver(I) ions in photographic film developing solution samples in FIP system. The results attained from FIP system were compared with the atomic absorption spectrophotometry (AAS) results by using student's t-test at 95 % confidence level and relative deviation (RD) between the two methods was < 8 %.
Pvc-Membrane Potentiometric Sensor for the Determination of Tamoxifen in Pharmaceutical Formulations
(Ieee-inst Electrical Electronics Engineers inc, 2015) Kanberoglu, Gulsah Saydan; Coldur, Fatih; Topcu, Cihan; Cubuk, Osman
Novel tamoxifen-selective potentiometric electrodes based on various ion associations of tamoxifen were developed. The most suitable membrane composition, which has the best potentiometric characteristics, was examined under steady-state conditions. The membrane composed of (w/w) 3% tamoxifen-phosphomolibdate ion pair, 32% poly(vinylchloride), and 65% 2-nitrophenyloctylether was determined as the membrane with the best analytical properties. On the condition of pH = 2-6, the fabricated electrode exhibited linear responses over the concentration range of 9.1 x 10(-6) -1 x 10(-3) M tamoxifen solutions (R-2 = 0.9989) with a sensitivity of 42.9 +/- 0.3 mV/decade, detection limit of 7.3 +/- 0.4 x 10(-6) M and short response time of approximate to 25 s. The influences of some alkaline, alkaline earth metals, biologically significant molecules, and some pharmaceutical species over electrode responses were studied. The proposed electrode was applied for the determination of tamoxifen contents of some pharmaceutical formulations by using standard addition method. The potentiometric analysis results obtained for the pharmaceutical formulations were in good harmony with the results obtained by high performance liquid chromatography at 95% confidence level.