Yazar "Citak, Meryem" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Direct Quantitative Determination of Total Arsenic in Natural Hotwaters by Anodic Stripping Voltammetry at the Rotating Lateral Gold Electrode
    (Bentham Science Publ Ltd, 2009) Yilmaz, Selehattin; Baba, Baris; Baba, Alper; Yagmur, Sultan; Citak, Meryem
    A simple, rapid, selective and sensitive differential pulse anodic stripping voltammetric (DPASV) technique for the direct quantitative determination of inorganic total arsenic in natural hotwater was developed. The electrochemical determination of total arsenic has been carried out at the novel rotating lateral gold electrode in hydrochloric acid solution (37 % w/w). The analysis was performed with a special gold electrode whose active surface was located on the side. Reproductivity of measurement was achieved by the conditioning of the gold electrode. This was done every day before the measurements as well as when the background current varied strongly from measurement to measurement. The determination limit of 0.5 mu g L-1 was achieved with 10 mL sample solution. The total arsenic concentration was made by appropriate selection of the deposition potential. During the deposition step, the total arsenic content was reduced at -1200 mV by nascent hydogen to As degrees. During the subsequent voltammetric determination, the preconcentration As degrees was again oxidized to determine the level. The method was applied successfully to the direct quantitative determination of total inorganic arsenic in hotwater. In order to show the accuracy of the results developed from voltammetric technique, the values obtained were compared with those obtained from inductively coupled plasma mass spectrometry (ICP-MS).
  • [ X ]
    Öğe
    Osteryoung square wave voltammetric determination of phenazopyridine hydrochloride in human urine and tablet dosage forms based on electrochemical reduction at carbon paste electrode
    (Bentham Science Publ Ltd, 2007) Citak, Meryem; Yilmaz, Selahattin; Dilgin, Yusuf; Tuerker, Guelen; Yagmur, Sultan; Erdugan, Hueseyin; Erdugan, Necla
    An electroanalytical method was developed for the direct quantitative determination of phenazopyridine hydrochloride (PAP) or in other words, pyridium, in spiked human urine and tablet dosage forms. The electrochemical reduction and determination of PAP were carried out at carbon paste electrode (CPE) in various aquaeous Solution in the pH range of 0.5-12.30 by (CV) and osteryoung square wave voltammetry (OSWV). The best results were obtained for the quantitative determination of PAP by OSWV method in 0.5 mol L-1 Sulfuric acid at about pH 0.51. The peak current and peak potential depend on pH and scan rate were studied. The diffusion controlled nature of the peak was established. This electroanalytical procedure made it possible to determine PAP in the concentration range 2.5x10(-8)-2.5x10(-6) mol L-1. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 7.5x10(-9) and 2.5x10(-8) mol L-1 respectively. Precision and accuracy of the developed method were checked by recovery studies in spiked urine and tablet dosage forms.