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Öğe Preparation of a novel ionic hybrid stationary phase by non-covalent functionalization of single-walled carbon nanotubes with amino-derivatized silica gel for fast HPLC separation of aromatic compounds(Elsevier, 2016-03) Aral, Hayriye; Çelik, Kadir Serdar; Aral, Tarık; Topal, GiraySingle-walled carbon nanotubes (SWCNTs) were immobilized on spherical silica gel with a 4-μm average particle size and a 60-Å average pore size. The amino-derivatized silica gel was non-covalently coated with carboxylated SWCNTs to preserve the structure of the nanotubes and their physico-chemical properties. The novel ionic hybrid stationary phase was characterized by scanning electron microscopy (SEM), infra-red (IR) spectroscopy and elemental analysis, and then, it was used to fill an empty 150×4.6 mm 2 high-performance liquid chromatography (HPLC) column. Chromatographic parameters, such as the theoretical plate number, retention factor and peak asymmetry factor, and analytical parameters, such as the limit of detection (LOD), limit of quantification (LOQ), linear range, calibration equation, and R 2 value, and quantitative analysis parameters were calculated for all of the analytes. Using different mobile phases, five different classes of aromatic hydrocarbons were separated in a very short analysis time of 4-8 min. Furthermore, a high theoretical plate number (up to 25000) and an excellent peak asymmetry factor (1.0) were obtained. The results showed that the surface of the SWNTs had very strong interactions with aromatic groups, therefore providing high selectivity for the separation of different classes of aromatic compounds. This study indicates that SWCNTs enable the extension of the application range of the newly prepared stationary phases for the fast separation of aromatic compounds by HPLC.Öğe Method validation and simultaneous determination of retinol, retinyl palmitate, β-Carotene, α-Tocopherol and vitamin C in Rat serum treated with 7,12 dimethylbenz[a]anthracene and plantago major L. By high- Performance liquid chromatography using diode-array detection(Bentham, 2013-02) Levent, Abdulkadir; Oto, Gökhan; Ekin, Suat; Berber, İsmetA new and simple high-performance liquid chromatography method was developed and validated for the simultaneous determination of retinol, retinyl palmitate, β-carotene, α-tocopherol and vitamin C in rat serum treated with Plantago Major L. and 7,12 dimethylbenz[a]anthracene. High-performance liquid chromatography analysis was performed utilizing an Inertsil ODS3 reversed phase column with methanol-tetrahydrofuran-water as mobile phase under gradient conditions, at 1.5 mL min-1 flow rate and 25 °C. Diode-array detection was at 325, 450, 290 and 270 nm (retinol and retinyl palmitate), β-carotene, α-tocopherol and vitamin C, respectively and runnig time 18 min. The high-performance liquid chromatography assay and extraction procedure proposed are simple, rapid, sensitive and accurate. The method was then applied for the determination of retinol, retinyl palmitate, β-carotene, α-tocopherol and vitamin C in rat serum. Results of this study demonstrated that; at 60th day DMBA-treated group, there was a significant decrease in vitamin levels compared to the levels of control group. A significant increase was observed in vitamin levels of 7,12 dimethylbenz[a]anthracene+Plantago Major L.-treated group compared to the DMBA-treated group. Additionally, the results obtained in the study are found to be in agreement with data reported in the literature.
