High resolution NMR spectroscopy and some examples of its use

Hopkins, C. Y.

doi:10.1007/bf02631954

Cited by 24 publications

(1 citation statement)

References 50 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The NMR spectrum of cyclopropene fatty acids in oils has also been well documented (13,14,18). The method of analysis employing 60 MHz or 100 MHz NMR instruments for the analysis of Sterculia foetida oil gave very low results for CPFA content in our experience.…”

Section: Introductionmentioning

confidence: 62%

Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Bland

Dine

Jobanputra

et al. 1984

J Americ Oil Chem Soc

View full text Add to dashboard Cite

Various concentrations of cyclopropene fatty acids have been determined down to 0.2% by the use of gas liquid chromatographic (GLC) analysis of the methyl esters of fatty acids that have been quantitatively hydrogenated using a homogeneous transition metal complex catalyst. The effectiveness of the use of bromotris(triphenylphosphine)-rhodium(I), Br(P(C~ H s)3)3 Rh, as a homogeneous hydrogenation catalyst to convert the cyclopropene ring to a cyclopropane ring has been evaluated and compared with the analogous chloro-and iodo-complexes. The hydrogenation/GLC method of analysis has been compared with the method of titration with hydrogen bromide in benzene and with the method involving the use of high resolution nuclear magnetic resonance (NMR).

show abstract

Section: Introductionmentioning

confidence: 62%

Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Bland

Dine

Jobanputra

et al. 1984

J Americ Oil Chem Soc

View full text Add to dashboard Cite

show abstract

Lipid Analyses in Food

Marini¹

2000

Encyclopedia of Analytical Chemistry

View full text Add to dashboard Cite

The term lipid encompasses a great host of compounds (e.g. fatty acids (FAs), mono‐, di‐ and triglycerides), that are almost ubiquitously present in foods; their characterization and quantification is then of importance for an analytical chemist. The first step for an accurate analysis is sample preparation: choosing an appropriate solvent or phases can isolate one particular class of lipid from a sample [a good separation of classes can be accomplised by thin‐layer chromatography (TLC)]; obviously, the sample pretreatment will be governed by the determinations to follow. Indeed, nowadays, there is a host of techniques, mainly chromatographic, for lipid analysis. TLC is a rapid way to gather information about the sample (presence of conjugated double and triple bonds, free FAs and of oxygenated FAs), particularly with the development of modified normal phases. For example, silica gel can be impregnated with boric acid, which inhibits isomerization of mono‐ and diglycerides, or it can be treated with silver ions [argentation, for silver ion thin‐layer chromatography (Ag‐TLC)] used for resolution of unsaturated FAs. Gas chromatography (GC) and high‐performance liquid chromatography (HPLC) are the most common techniques actually employed, because of their versatility (many parameters can be changed, e.g. stationary and mobile phases, detector) and to their capacity to be hyphenated (coupled with another measuring device). Particularly, the advent of the light‐scattering detector has allowed greater reproducibility in the HPLC of lipids. Mass spectrometry (MS) is often coupled with GC. However, coupling MS with another MS (MS/MS or tandem MS) is useful for the determination of the structure of long‐chain FAs with improved selectivity and sensitivity. Finally, nuclear magnetic resonance (NMR) is able to identify functional groups, even in mixtures, and is a valid aid for the elucidation of structures with double bonds (DBs) by interpretation of the coupling patterns. Each analytical method relies on appropriate sample preparation (e.g. methylation for the GC analysis of FAs) and a critical approach to evaluate its usefulness.

show abstract

Chemie und Biochemie ungesättigter Fettsäuren

Kunau

1976

Angewandte Chemie

View full text Add to dashboard Cite

Obwohl man schon seit langem weiD, daD ungedttigte Fettsauren neben gesittigten Fettsiuren in den meisten Lipiden vorkommen, haben es erst die modernen Analysenmethoden ermoglicht. Fettduremuster qualitativ und quantitativ zu bestimmen. Die heutigen Kenntnisse uber die chemische Struktur, die physikalischen Eigenschaften und den Stoffwechsel ungesattigter Fettsauren bilden die Grundlage fur die Entwicklung neuer Vorstellungen uber ihre Funktion. Danach bestimmen die ungedttigten Fettsiuren wesentlich die Eigenschaften von biologischen Membranen. AuDerdem sind die essentiellen Fettduren Vorstufen fur die Prostaglandine.

show abstract

High resolution NMR spectroscopy and some examples of its use

Cited by 24 publications

References 50 publications

Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Lipid Analyses in Food

Chemie und Biochemie ungesättigter Fettsäuren

Contact Info

Product

Resources

About