Yazar "Aydoğan, Cemil" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Cation exchange/hydrophobic interaction monolithic chromatography of small molecules and proteins by nano liquid chromatography(Wiley-V C H Verlag Gmbh, 2013) Aydoğan, Cemil; Yılmaz, Fatma; Denizli, AdilIn this study, vinyl phenyl boronic acid modified lauryl methacrylate-based monolithic column was successfully prepared for cation exchange/hydrophobic interaction monolithic chromatography of small molecules and proteins in nano LC. The polymeric mixture consisted of lauryl methacrylate, vinyl phenyl boronic acid as cation exchanger, ethylene dimethacrylate as cross-linker, polyethylene glycol and methanol as binary porogenic solvent, and azobisisobutyronitrile as initiator. The resulting monolith showed good permeability and mechanical stability. Different ratios of monomer and porogens were used for optimizing the properties of the column. The monolithic column performance with respect to hydrophobic and cation exchange interactions was assessed by the separation a series of alkyl benzenes and anilines, respectively. cis-Diol-containing compounds such as phenols were also utilized to evaluate the retention behaviors of the vinyl phenyl boronic acid modified monolithic column. The monolithic column showed cation exchange interactions in the separation of aniline compounds. Theoretical plate number up to 52 000 plates/m was successfully achieved. The prepared monolith was further applied to the proteins with different acetonitrile content.Öğe Enantioseparation of aromatic amino acids using CEC monolith with novel chiral selector, N-methacryloyl-L-histidine methyl ester(Wiley, 2013) Aydoğan, Cemil; Yılmaz, Fatma; Çimen, Duygu; Uzun, Lokman; Denizli, AdilA new type of polymethacrylate-based monolithic column with chiral stationary phase was prepared for the enantioseparation of aromatic amino acids, namely d,l-phenylalanine, d,l-tyrosine, and d,l-tryptophan by CEC. The monolithic column was prepared by in situ polymerization of butyl methacrylate (BMA), N-methacryloyl-l-histidine methyl ester (MAH), and ethylene dimethacrylate (EDMA) in the presence of porogens. The porogen mixture included DMF and phosphate buffer. MAH was used as a chiral selector. FTIR spectrum of the polymethacrylate-based monolith showed that MAH was incorporated into the polymeric structure via in situ polymerization. Some experimental parameters including pH, concentration of the mobile phase, and MAH concentration with regard to the chiral CEC separation were investigated. Single enantiomers and enantiomer mixtures of the amino acids were separately injected into the monolithic column. It was observed that l-enantiomers of aromatic amino acids migrated before d-enantiomers. The reversal enantiomer migration order for tryptophan was observed upon changing of pH. Using the chiral monolithic column (100 m id and 375 m od), the best chiral separation was performed in 35:65% ACN/phosphate buffer (pH 8.0, 10mM) with an applied voltage of 12 kV in CEC. SEM images showed that the chiral monolithic column has a continuous polymeric skeleton and large through-pore structure.Öğe A new zwitterionic electrochromatographic stationary phase based on poly(3-chloro-2-hydroxypropyl methacrylate-co-ethylene dimethacrylate) reactive monolith(Wiley-Blackwell, 2014) Aydoğan, Cemil; Çelebi, Bekir; Bayraktar, Aslıhan; Yılmaz, Fatma; Denizli, AdilA new reactive monolith, poly(3-chloro-2-hydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(HPMA-Cl-co-EDMA) was synthesized and post-functionalized by taurine (2-aminoethane sulfonic acid) to obtain a zwitterionic stationary phase for capillary electrochromatography. The new stationary phase contained charged groups such as secondary amine providing anodic electroosmotic flow and sulfonic acid groups providing cathodic electroosmotic flow. Hence, the capillary electrochromatography separations with the new zwitterionic monolith were performed with either anodic or cathodic electroosmotic flow. The electrochromatographic separation of alkylbenzenes and phenols was successfully performed. The zwitterionic monolith also allowed the separation of nucleosides using only electrokinetic mode. Theoretical plate numbers up to similar to 10(5) plates/m were achieved. Our study is the first report based on poly(HPMA-Cl-co-EDMA) reactive monolith post-functionalized with a zwitterionic ligand allowing to operate in both anodic and cathodic electroosmotic flow modes. Copyright (C) 2014 John Wiley & Sons, Ltd.Öğe Study on an Hydrophilic Interaction Electrochromatography Method for Separation of Sulfonamide Antibiotics(2014) Aydoğan, Cemil; Yılmaz, Fatma; Çimen, Duygu; Andaç, Müge; Shaikh, Huma; Denizli, AdilThis study describes the preparation of a hydrophilic monolithic column and its application to sulfonamide antibiotics. The column was prepared by single step in situ polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA) and methacrylic acid (MAA) in a binary porogenic solvent consisting of toluene and 1-dodecanol, inside a 100 µm-i.d. capillary. The resulting monolith was electrochromatographically characterized as well as SEM. The prepared column showed hydrophilic behaviour using thiourea and toluene as markers. The SEM images showed that the monolithic column composed of spherical particles of approximately 2 µm in diameter. Using this hydrophilic monolith as stationary phase, hydrophilic interaction electrochromatography of sulfonamide antibiotics as a new method was developed. The method was successfully used for the separation of sulfonamide antibiotics. Some parameters including acetonitrile (ACN) content, pH and ionic strength on the separation of the sulfonamides, namely sulfaprydine, sulfadiazine, sulfamethazine, sulfisoxazole and sulfadoxine were also investigated. A typical hydrophilic interaction separation mechanism was revealed at higher organic solvent content (ACN > 60%).
