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Normal-phase HPLC (normal-phase + hplc)
Selected AbstractsCharacterization of Azerbaijani and Croatian brown naphthalaneJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2005Andja Alajbeg Abstract In spite of the fact that noncolored (nonaromatic) naphthalane containing high sterane content has been proved as bioactive and efficient in the treatment of psoriasis vulgaris, brown naphthalanes, which contain aromatics, are still in use. Thousands of patients, who have been passing through the therapy, deserve thorough and permanent study of brown naphthalanes. For that reason, two frequently used brown naphthalane preparations, one of the Azerbaijani (N1) and the other of the Croatian (N2) origin, were studied. The samples underwent the study by means of GC, OT LC, and normal-phase HPLC, as separation techniques. In addition, some bulk properties, elemental composition, and group composition by 1H NMR were determined. GC-MS served in compound types, especially in sterane detection. Both of the samples were found to be unresolved complex mixtures, relatively poor in n -alkanes. Isoalkanes, cycloalkanes, and aromatic compounds, in a great variety of isomers and homologs, made the majority of both of the samples. N1 was a dark, viscous, nontransparent fluid with a strong petroleum smell. Aromatics, which made 53% mass by OT LC and 54% mass by 1H NMR were found to be composed of mono-, di-, and tri+-aromatic compounds. Tri+-aromatic compounds were three to four times more abundant in N1 than in N2. Beside hydrocarbons, N1 comprised some organic compounds with polar functional groups. Also, some asphaltenes were found in it. N1 contained well-presented steranes, which are thought to be bioactive naphthalane ingredients. N2 was a pale brown liquid, with smell similar to gasoline. It contained somewhat lower percentage of aromatics (46% mass) and comparatively lower percentage of tri+ fused aromatics among which carcinogens might be expected. N2 was almost purely composed of hydrocarbons. It seemed to contain low content of steranes due to relatively low upper temperature of the distillation range applied in N2 preparation. [source] Quantitative analysis of polymeric proanthocyanidins in birch leaves with normal-phase HPLCPHYTOCHEMICAL ANALYSIS, Issue 3 2006Maarit Karonen Abstract The proanthocyanidin composition and content in the leaves of nine birch species (Betula albosinensis, B. ermanii, B. maximowicziana, B. nana, B. papyrifera, B. pendula, B. platyphylla, B. pubescens, and B. pubescens ssp. czerepanovii) were studied with different methods including colorimetric assay, HPLC coupled with PAD or ESI/MS and NMR. Total proanthocyanidin content was determined using the acid butanol assay. A normal phase-HPLC method was applied for the analysis of polymeric proanthocyanidins. The content of polymeric proanthocyanidins was estimated from a late eluting peak in the chromatogram. With this HPLC method, quantitative analysis of polymeric proanthocyanidins could be performed directly from leaf extracts: no additional purification or preparation steps were required. It was shown that birch leaves contained mainly polymeric proanthocyanidins with a degree of polymerisation greater than 10. Total proanthocyanidin content (expressed as dry weight) was found to vary from 44 mg/g (B. papyrifera) to 145 mg/g (B. nana), and polymeric proanthocyanidin content from 39 mg/g (B. pendula) to 119 mg/g (B. nana). Copyright © 2006 John Wiley & Sons, Ltd. [source] Structural analysis of ,-Gal and new non-Gal carbohydrate epitopes from specific pathogen-free miniature pig kidneyPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 13 2008Yun-Gon Kim Abstract The major barrier in transplantation of pig organs into humans is the presence of surface carbohydrate antigens (e.g., the Gal,1-3Gal,1-4GlcNAc-R (,-Gal) epitope) expressed on pig endothelial cells. In this study, total N -glycans from membrane glycoproteins derived from specific pathogen-free miniature pig kidney are identified by MALDI-TOF, negative ion ESI MS/MS and normal-phase HPLC (NP-HPLC) combined with exoglycosidase digestion. Over 100 N -glycans, including sialylated and neutral types, were identified. As well as the known ,-Gal antigens, some of these glycans contained novel non-Gal carbohydrate antigens such as (Neu5Gc-Gal-GlcNAc) and Gal,1-3Lewisx (Gal-Gal-(Fuc)GlcNAc) which have not been reported before in N -glycans from pig organs. The ability of MALDI, ESI, and HPLC to measure the relative proportions of the glycans was evaluated. The HPLC resolution was insufficient for accurate work and some minor differences were noted in the ionization efficiencies of different glycan groups when measured by the two mass spectrometric techniques. However, the results indicated that the relative quantity of ,-Gal epitope was in the region of 50% of the complex glycans. High-mannose type glycans were also abundant (35,43%) but appeared to be ionized more efficiently than the complex glycans by ESI than by MALDI. [source] Separation of chiral phosphorus compounds on the substituted ,-cyclodextrin stationary phase in normal-phase liquid chromatographyCHINESE JOURNAL OF CHEMISTRY, Issue 4 2000Chen Hyi Abstract The separation of enantiomers of a series of eighteen novel nitrogen mustard linked phosphoryl diamide derivatives was investigated on the prepared phenyl carbamate derivative ,-cyclodextrin bonded phase in normal-phase HPLC. Some of the enantiomers could be separated in baseline. The chiral recognition mechanism was also suggested for the separation of chiral phosphorus organic compounds. [source] | ||||||||||