摘要:

Abstractγ‐Linolenic acid (6c,9c,12c‐18:3) has recently become important for dietary and pharmaceutical applications. The reported occurrence of γ‐linolenic acid in seed oils from plant families known to produce fatty acids, including 18:3 acids, with Δ5‐cisand Δ5‐transdouble bonds makes it necessary to distinguish between 5c,9c,12c‐, 5t,9c,12c‐ and 6c,9c,12c‐octadecatrienoic acids by gas chromatography (GC) alone in routine screening operations. The separation of these acids using two different capillary GC systems has been investigated. The successful separation of octadecatrienoic acids with 5c, 5t and 6c double bonds is shown by way of gas chromatograms of the fatty acid methyl esters obtained from the seed oils of four different species of the family Ranunculaceae and of

ISSN:0958-0344    

DOI:10.1002/pca.2800040602

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractMethoxyoxime acetates of carbohydrates and partially methylated derivatives were easily separated by high resolution gas chromatography (HRGC) and showed characteristic mass spectra (MS). Thus, the conversion of carbohydrates to the corresponding methoxyoxime acetates offers an attractive derivatization for subsequent HRGC and HRGC/MS analysis of carbohydrates, particularly in glycoconjugates of plant origin.

ISSN:0958-0344    

DOI:10.1002/pca.2800040603

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA quantitative1H NMR procedure for the determination of bilobalide and ginkgolides A, B, C and J inGinkgo bilobaleaves and in phytopharmaceuticals without prior chromatographic separation of the mixture has been developed. The method is based on the comparison of the integral of each H‐12 proton of the five ginkgo terpene trilactones with that of the olefinic protons of the internal standard (maleic acid). These protons are all well separated at 200 MHz and occur in a less crowded region of the NMR spectrum (6.15‐6.50 ppm). The selectivity, reproducibility and sensitivity are comparable with high pressure liquid chromatography (HPLC) with refractive index (RI) detection. The minimum amount that can be quantified within 30 min at 200 MHz is approximately 0.1 mg for all four ginkgolides and bilobalide. Advantages, in comparison with HPLC‐RI, are that no reference substances are needed and that for the occasional analysis of a limited number of samples a very significant time‐gain can be a

ISSN:0958-0344    

DOI:10.1002/pca.2800040604

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe chemical characterization of the saponins and sapogenins isolated from roots and aerial parts of two alfalfa cultivars with differing saponin content is reported. A procedure for the extraction and quantification of saponins is described, and the identification of the major components of the saponin mixture has been performed using thin layer chromatography and high performance liquid chromatography. Characterization, using gas chromatography (GC) and GC/mass spectral analysis, of sapogenins released following acid hydrolysis allowed the identification of medicagenic acid, hederagenin, soyasapogenols B, C, D, E and F as the major compounds, together with oleanolic acid. Quantitative analysis of the sapogenins in aerial parts and roots of the two cultivars is reported and discussed.

ISSN:0958-0344    

DOI:10.1002/pca.2800040605

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractSome hydroxy‐ and methoxy‐substituted flavones have been studied following carbon dioxide supercritical fluid chromatography on polymethylsiloxane capillary columns using flame ionization and Fourier transform infrared spectroscopic detection. The separation was performed without the use of a phase modif

ISSN:0958-0344    

DOI:10.1002/pca.2800040606

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractOptimal extraction methods and Reversed‐Phase High Performance Liquid Chromatographic (RP‐HPLC) procedures were developed for the isolation and resolution of naturally occurring flavonoids and related phenolic compounds inRosapetals. The following flavonoids and related phenolics were identified or partly identified: cyanidin 3, 5‐di‐O‐glucoside; cyanidin 3, 5‐di‐O‐glycoside (sugar moieties, glucose and arabinose); pelargonidin 3, 5‐di‐O‐glycoside; pelargonidin 3‐O‐glycoside; quercetin 3‐O‐glucoside; ellagic acid; quercetin 3‐O‐arabinoside; quercetin 4′‐O‐glucoside; kaempferol 4′‐O‐glucoside; kaempferol 3‐O‐rutinoside; kaempferol 3‐O‐glycoside; kaempferol 3‐O‐arabinoside; kaempferol 3‐O‐rhamnoside and kaempferol 3‐O‐glycoside. Significant qualitative and quantitative differences between the above flavonoid markers allowed an objective distinction between 44 cultivars examined. The production of ‘Flower Flavonoid RP‐HPLC Fingerprints’, which have been converted in the corresponding ‘Computer Flower Flavonoid Identity Cards’ via a suitable co

ISSN:0958-0344    

DOI:10.1002/pca.2800040607

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800040609

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800040610

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

ISSN:0958-0344    

DOI:10.1002/pca.2800040601

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY