title: Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications.
abstract: A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation conditions for seven phenolic compounds was also achieved using reversed-phase HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and seven phenolic compounds could be separated and detected at 230 nm within 16 min.
authors.affiliation: University of Batman, Faculty of Science and Art, Department of Chemistry, Batman, Turkey. Electronic address: tarik.aral@batman.edu.tr.
authors.forename: Tarık
authors.initials: T
authors.lastname: Aral
authors.affiliation: University of Batman, Faculty of Science and Art, Department of Chemistry, Batman, Turkey. Electronic address: hayriye.aral@batman.edu.tr.
authors.forename: Hayriye
authors.initials: H
authors.lastname: Aral
authors.affiliation: University of Dicle, Faculty of Science, Department of Chemistry, Diyarbakır, Turkey.
authors.forename: Berrin
authors.initials: B
authors.lastname: Ziyadanoğulları
authors.affiliation: University of Dicle, Faculty of Science, Department of Chemistry, Diyarbakır, Turkey.
authors.forename: Recep
authors.initials: R
authors.lastname: Ziyadanoğulları
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000814:Aniline Compounds / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D005973:Glutamine / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D009705:Nucleosides / Q000302:isolation & purification*; D010636:Phenols / Q000302:isolation & purification*; D010937:Plant Growth Regulators / Q000302:isolation & purification*; D058428:Silica Gel / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000814:Aniline Compounds; D009705:Nucleosides; D010636:Phenols; D010937:Plant Growth Regulators; D005973:Glutamine; D058428:Silica Gel; C023650:aniline; C032159:acetonitrile
keywords: HILIC; Mixed-model stationary phase; Nucleotides and nucleosides; Phenolic compounds; Phytohormones; Polar stationary phase