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    Öğe
    Electrocatalytic effect of nano-wrinkled layer carbonaceous electrode: determination of folic acid by differential pulse voltammetry
    (Springer International Publishing Ag, 2019) Erkal-Aytemur, Aslı; Üstündağ, İlknur; Kariper, İshak Afşin; Çağlayan, Mustafa Oğuzhan; Üstündağ, Zafer
    Nano-wrinkled layer carbonaceous electrode materials were prepared from pyrolytic carbonization of different proportions of mixtures coal tar pitch (CTP) and polystyrene (PS) composite. The PS content in carbonaceous materials was in between 10% and 70% PS. The electrodes were characterized using scanning electron microscopy (SEM) and electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CTP-PS4 (50% PS content) electrode was more reductant than the other electrodes. Similarly, electrocatalytic activity of CTP-PS4 for folic acid (FA) was higher than the other electrodes. The electrode was used in the determination of FA by differential pulse voltammetry (DPV). Under optimal conditions, the anodic current of FA was linear in the concentration range from 0.25 to 40 mu mol/L. The obtained linear range calibration plot of the concentration of FA vs. peak current resulted in two linear slope values. The first equation for FA was Ip(FA)=0.2476+3.9005 [FA] (R-2: 0.9970) with the linear range from 0.25 to 1.5mol/L (LOD: 0.011mol/L; S/N=3). The second linear equation was Ip(FA)=4.5377+1.2509 [FA] (R-2: 0,9957) with the linear range from 3.0 to 40mol/L (LOD=0.092mol/L; S/N=3). The proposed method was applied for the determination of FA in human serum with recovery rate from 97.3 to 101.3%.
  • [ X ]
    Öğe
    Electrochemical Detection of Cadmium and Lead in Rice on Manganese dioxide Reinforced Carboxylated Graphene Oxide Nanofilm
    (Kyrgyz-Turkish Manas University, 2018) Üstündağ, İlknur; Erkal, Aslı; Üstündağ, Zafer; Solak, Ali Osman
    Manganese dioxide decorated carboxylated graphene oxide (Mn-GO-COOH) attached onto the glassy carbon (GC) electrode to develop a new method for the simultaneous determination of Cd2+ and Pb2+ ions in rice samples. Graphene oxide (GO) was attached on 4-aminophenyl covalently modified glassy carbon surface via amide reaction. As-prepared modified material was characterized with XPS, SEM and electrochemical methods. A novel differential pulse anodic stripping voltammetric (DPASV) method was developed for the simultaneous determination of Cd2+ and Pb2+ on the GC/Mn-GO-COOH nanoplatform electrode. A linear response was found for the heavy metals in the range from 5 to 100 mg/L. The limit of detections (LODs) of Cd2+ and Pb2+ were 0.04 mg/L and 0.08 mg/L respectively. Manganese dioxide decorated carboxylated graphene oxide electrode was applied to the detection of Cd2+ and Pb2+ present in different rice samples by developed voltammetric method, and the accessed results were found to be in accordance with that of ICP-OES.