Dialkyl L-glutamide-derived lipids have been found to form supramolecular assemblies and to show specific properties based on their highly ordered structures in aqueous and organic media. To use these unique properties to create molecular recognition systems, dioctadecyl L-glutamide-derived lipid-grafted porous silica particles (Sil-DSG) were newly prepared and used as a stationary phase in reversed phase liquid chromatography. Compared with conventional ODS (octadecylated silica), the Sil-DSG column showed remarkably higher selectivity for polycyclic aromatic hydrocarbons (PAHs). Especially, Sil-DSG recognized the molecular linearity and planarity of PAHs. Suspension state 1H NMR and 13C CP/MAS-NMR spectroscopies showed that the alkyl chains on the Sil-DSG are in gauche form and their mobility is strongly restricted at room temperature. This paper discusses higher selectivity of Sil-DSG with a carbonyl pi-benzene pi interactions.
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http://dx.doi.org/10.1016/j.chroma.2005.03.090 | DOI Listing |
Talanta
January 2009
Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kumamoto University, Kumamoto, Japan.
Two dioctadecyl L-glutamic acid derivatives with amide and ester type bondings have been synthesized and immobilized from 3-aminopropyltrimethoxysilane (APS) grafted silica (Sil-APS) to be used in reversed-phase high-performance liquid chromatography (RP-HPLC). Subsequent studies showed that dioctadecyl-L-glutamide derivative (GLN) can self-assemble into highly ordered structures by forming three-dimensional fibrillar aggregates as observed in scanning and transmission electron microscopes (SEM and TEM). Variable temperature (1)H NMR and FT-IR spectra of organogel revealed that the special aggregation morphology shown by GLN was stabilized by inter and or intra molecular hydrogen bonding among amide moieties.
View Article and Find Full Text PDFJ Chromatogr A
June 2006
Department of Applied Chemistry and Biochemistry, Kumamoto University, Japan.
Double alkylated L-glutamide-derived noncrystalline stationary phases Sil-DSG and Sil-DBG have been prepared by coupling N',N''-dioctadecyl-N-[4-carboxybutanoyl]-L-glutamide (DSG) and N',N'',-dibutyl-N-[4-carboxybutanoyl]-L-glutamide (DBG) with aminopropylated silica (Sil-APS). TEM observations of DSG and DBG showed that lipid DSG can aggregate in organic solvents (methanol, chloroform, toluene, etc.) and self-assembled nano fibers are observed while such fibrous aggregations are not observed for DBG.
View Article and Find Full Text PDFJ Chromatogr A
May 2005
Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto, Japan.
Dialkyl L-glutamide-derived lipids have been found to form supramolecular assemblies and to show specific properties based on their highly ordered structures in aqueous and organic media. To use these unique properties to create molecular recognition systems, dioctadecyl L-glutamide-derived lipid-grafted porous silica particles (Sil-DSG) were newly prepared and used as a stationary phase in reversed phase liquid chromatography. Compared with conventional ODS (octadecylated silica), the Sil-DSG column showed remarkably higher selectivity for polycyclic aromatic hydrocarbons (PAHs).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!