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Öğe Kiral tetraamid jelatörleri(Erzurum Atatürk Üniversitesi, 2018-03) Aral, Tarık; Aral, Hayriye; Sünkür, Murat; Barış Cebe, DenizÖğe Synthesis, characterization and application of a novel multifunctional stationary phase for hydrophilic interaction/reversed phase mixed-mode chromatography(Talanta, 2017-11-1) Aral, Tarık; Aral, Hayriye; Çelik, Kadir Serdar; Altındağ, RamazanA novel multifunctional stationary phase based on silica gel was synthesised starting from L- isoleucine and 4-phenylbutylamine and evaluated as a hydrophilic interaction/reversed-phase mixed-mode stationary phase for high-performance liquid chromatography (HPLC). The prepared stationary phase was characterized by elemental analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM), Brunauer, Emmett and Teller (BET) and solid-state 13C nuclear magnetic resonance (NMR). The mechanisms involved in the chromatographic separation are multi-interaction, including hydrophobic, π-π, hydrogen-bonding, dipole-dipole and ion-dipole interactions. Based on these interactions, successful separation could be achieved among several aromatic compounds having different polarities under both hydrophilic interaction liquid chromatography (HILIC) and reversed phase (RP) condition. Nucleotides/nucleosides were separated in the HILIC mode. The effects of different separation conditions, such as pH value, mobile-phase content, column temperature, buffer concentration and flow rate, on the separation of nucleotides/nucleosides in HILIC mode were investigated. The seven nucleotides/nucleosides were separated within 22 min, while six of them were separated within 10 min by isocratic elution. To determine the influence of the new multifunctional stationary phase under the RP condition, a number of moderately and weakly polar and nonpolar compounds, such as 10 substituted anilines and eight substituted phenols were separated successfully under the RP condition within 14 and 15 min, respectively. Additionally, nine mixtures of polar/nonpolar test compounds were simultaneously separated within 19 min, while seven of them were separated within 12 min, under HILIC/RP mixed-mode conditions. Chromatographic parameters, such as the retention factor and peak asymmetry factor, were calculated for all of the analytes, while the theoretical plate number was calculated for analytes separated by isocratic elution. Compared to traditional C18 and commercial HILIC columns, the new stationary phase exhibited both HILIC and RPLC performance, and the scope of analyte separation was thus enlarged.Öğe Polar HPLC sabit fazlarında son gelişmeler: Mixed-Mode kromatografi(Hitit Üniversitesi, 2017-09) Aral, Tarık; Aral, Hayriye; Altındağ, Ramazan; Çelik, Kadir SerdarSabit faz kromatografinin ana unsurudur. Özellikle HPLC’de sabit fazın önemi çok büyüktür. Ayırma mekanizması, ayırma selektivitesi ve kolon etkinliği dolgu maddesinin yapısına bağlıdır. Geleneksel sabit fazlar (NP ve RP)da ayırma mekanizması tek bir etkileşime dayanırken mixed model sabit fazlarda bir çok ayırma mekanizması geçerlidir. Polar dolgu fazları yapılarına göre üç gruba ayrılır: Polar gömülü, polar HILIC ve polar mixed-mode1. Bir dolgu maddesinin mixed-mode olarak nitelendirilmesi için analitlerle en az iki farklı etkileşim göstermelidir. Geleneksel dolgu maddeleri ile kıyaslandığında, bu farklı etkileşim türleri büyük avantaj sağlar: yüksek ayırma selektivitesi, yüksek bağlanma kapasitesi ve yüksek kolon etkinliği (teorik tabaka sayısı) v.b. 2. Son birkaç yılda mixed-mode sabit fazlar üzerine çalışmalar ve bu alana olan ilgi hızla artmaktadır. Çok sayıda mixed-mode sabit faz hazırlanmış olup polardan apolara pek çok analit grubunun ayrılmasında tek bir kolon başarı ile kullanılmıştır 3. Geleneksel ters faz kolonlar düşük ve orta polarlıktaki bileşiklerin ayrılmasında başarı ile kullanılırken mixed-mode kolonlar düşük polariteden çok yüksek polariteye sahip çok farklı analit gruplarının ayrılmasında da kullanılabilmektedir. Böylece bir mixed-mode kolon hem ters faz hem HILIC hem normal faz kolon görevi görmüş olur1. Grubumuz 2012 yılından beri mixed-mode sabit fazlar üzerine çalışmakta, bu alanın gelişimine önemli katkılar sağlamaktadır [4-5]. Genellikle doğal amino asit bileşiklerinden yola çıkılarak geliştirdiğimiz farklı yapıdaki mixed-mode sabit fazlar ile pek çok polar-apolar bileşik sınıfı başarı ile ayrılmış olup, hazırlanan kolonlar ticari kolonlar ile yarışacak, ticari kolonlara alternatif olabilecek niteliktedir. Bu sunum kapsamında, öncelikli olarak kendi çalışmalarımızdan oluşan son yıllarda mixedmode kromatografi alanındaki gelişmelerin kısa bir özeti sunulacaktır.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 Separation, optimization, and quantification of cytokinins by a recently developed amide-embedded stationary phase(Taylor & Francis, 2017-07-06) Aral, Hayriye; Haşimi, Duygu; Aral, Tarık; Levent, Abdulkadir; Ziyadanoğulları, BerrinIn this study, some plant growth regulators known as cytokinins [kinetin (K), zeatin (Z), thidiazuron (TDZ), benzylaminopurine (BAP), and dimethylallylaminopurine (AAP)] were separated by HPLC using an amide-embedded mixed-mode stationary phase which was synthesized by Aral et al. in recent years. The effect of mobile phase content, mobile phase pH, buffer concentration, and temperature on separation process was studied. In addition, a quantitative determination of cytokinins from Salvia limbata extract was studied, and some validation parameters such as limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) were calculated as a range of 0.03–0.1, 0.1–0.26 mg/L, and 0.03–0.08, respectively.Öğe Potansiyel ilaç taşıyıcı sistem olarak tetraamid jelatörler(Erzurum Atatürk Üniversitesi, 2018-03) Aral, Tarık; Aral, Hayriye; Barış Cebe, Deniz; Sünkür, MuratÖğe Yeni bir amid silika dolgu maddesinin sentezi ve hidrofilik etkileşim sıvı kromatografisi (HILIC) uygulamaları(Mustafa Kemal Üniversitesi, 2012-09) Aral, Tarık; Aral, Hayriye; Ziyadanoğulları, Berrin; Ziyadanoğulları, RecepÖğe Amid-silika türevi polar faz yeni bir kolon dolgu materyalinin sentezi ve çeşitli polar analitlerin ayrılması(Muğla Üniversitesi, 2012-10) Aral, Tarık; Aral, Hayriye; Ziyadanoğulları, BerrinÖğe Optimised HILIC separation and method validation of b vitamins using a mixed-mode stationary phase(Fırat Üniversitesi, 2017-10) Aral, Tarık; Aral, Hayriye; Çelik, Kadir Serdar; Altındağ, RamazanÖğe HPLC separation of different groups of small polar compounds on a novel amide-embedded stationary phase(Elsevier, 2014-05-10) Aral, Hayriye; Aral, Tarık; Çelik, Kadir Serdar; Ziyadanoğulları, Berrin; Ziyadanoğulları, RecepRetention behaviors of an amide-embedded silica base stationary phase, which was recently developed by our group, were studied by using six different groups of small polar compounds including phenolic compounds, substituted anilines, chlorinated herbicides, Sudan dyes and some nucleotides and nucleosides in HPLC. The chromatographic behaviors of the prepared stationary phase for these analytes were compared with those of a commercially available reversed-phase column ACE C18 under same conditions. Among the six groups of analytes studied, the amide-silica stationary phase showed enhanced selectivity towards phenolic compounds, substituted anilines, Sudan dyes and herbicides under reversed-phase conditions and satisfactory selectivity towards nucleosides and nucleotides which could not be separated with ACE C18 column under HILIC conditions. Experimental data provided some evidence that functional groups on the stationary phases might have certain degrees of influence on selectivity possibly through secondary interactions with the model compounds. The retentions of the moderately polar compounds such as phenolic acids, anilines and herbicides on the stationary phase are higher than highly polar compounds such as nucleotides and nucleosides due to both the hydrophobic and hydrophilic interactions between the stationary phase and analytes. The quantitative determination of Sudan dyes (I, II, III, and IV) in red chilli peppers was performed. Many red chilli peppers were screened and three of them contained Sudans dyes.
