Matches in SemOpenAlex for { <https://semopenalex.org/work/W3025425618> ?p ?o ?g. }
Showing items 1 to 57 of
57
with 100 items per page.
- W3025425618 abstract "Steroidal compounds are virtually ubiquitous in nature and frequently occur in complex mixtures as constituents of closely similar structure. Packed column gas chromatography-mass spectrometry (GC-MS) is an analytical technique of unique facility for the simultaneous separation and characterisation of complex mixtures of organic compounds. This thesis examines the additional facility provided by glass open tubular gas chromatographic columns of higher efficiency in the analysis by GC and GC-MS of complex mixtures of steroidal compounds derived from a number of natural sources. A method for the preparation of stable, efficient and reproducible glass open tubular gas chromatographic columns is described. The construction of chromatographic systems adapted to their somewhat more critical requirements is outlined. Particular attention is paid to the requirements for the interface of these columns to an LKB 9000 combined gas chromatograph-mass spectrometer. The performance of this system with emphasis on the nature of the advantage obtained over conventional packed columns is demonstrated by several model of mixtures of closely related standard steroidal compounds. Mixtures of sterols derived from yeast and marine sources frequently consist in mixtures of components differing in the degree and position of alkylation and unsaturation in the basic cholestanol structure. Correlation of gas chromatographic retention, on glass open tubular columns of OV-1 stationary phase, with sterol structure is described. Complementary data available in the literature are integrated into a scheme for the rationalisation of increments of Kovats retention index associated with particular alterations in sterol structure. This system and mass spectral correlations obtained by glass open tubular GC-MS is applied to the analysis of sterol mixtures derived from five species of marine invertebrate and two mutant strains of the yeast Candida albicans. Two other applications to sterol analysis are also described. A significant advantage is demonstrated over GC and GC-MS methods heretofore employed. Mixtures of hydroxy and ketosteroids may be derivatised as the alkyloxime-trimethylsilyl ether derivatives for GC and GC-MS analysis. The occurrence of syn- and anti-isomers in the alkyloximes of various ketosteroid structures is a complicating factor in their GC analysis, in particular at higher column efficiencies. Several alkyloximes of increasing hulk of the O-alkyl substituent were examined in this respect. The methyloxime is shown to provide the least complications for open tubular GC, though the group separations of hydroxy and ketosteroids provided by the higher alkyloximes may provide useful correlations. The utility of this approach is demonstrated in the analysis of mixtures of standard hydroxy and ketosteroids. Preliminary results obtained on a mixture of urinary steroid hormone metabolites of the human newborn by open tubular GC-MS of the isopentyloxime-trimethylsilyl ether derivatives are reported." @default.
- W3025425618 created "2020-05-21" @default.
- W3025425618 creator A5009895356 @default.
- W3025425618 date "1977-01-01" @default.
- W3025425618 modified "2023-09-27" @default.
- W3025425618 title "The Application of Combined Gas Chromatography-Mass Spectrometry to Compounds of Biological Interest: Steroid Analysis by the Use of Glass Open Tubular Gas Chromatographic Columns" @default.
- W3025425618 hasPublicationYear "1977" @default.
- W3025425618 type Work @default.
- W3025425618 sameAs 3025425618 @default.
- W3025425618 citedByCount "0" @default.
- W3025425618 crossrefType "dissertation" @default.
- W3025425618 hasAuthorship W3025425618A5009895356 @default.
- W3025425618 hasConcept C113196181 @default.
- W3025425618 hasConcept C123460561 @default.
- W3025425618 hasConcept C162356407 @default.
- W3025425618 hasConcept C185592680 @default.
- W3025425618 hasConcept C201268389 @default.
- W3025425618 hasConcept C205345274 @default.
- W3025425618 hasConcept C43617362 @default.
- W3025425618 hasConcept C72850032 @default.
- W3025425618 hasConcept C85666147 @default.
- W3025425618 hasConceptScore W3025425618C113196181 @default.
- W3025425618 hasConceptScore W3025425618C123460561 @default.
- W3025425618 hasConceptScore W3025425618C162356407 @default.
- W3025425618 hasConceptScore W3025425618C185592680 @default.
- W3025425618 hasConceptScore W3025425618C201268389 @default.
- W3025425618 hasConceptScore W3025425618C205345274 @default.
- W3025425618 hasConceptScore W3025425618C43617362 @default.
- W3025425618 hasConceptScore W3025425618C72850032 @default.
- W3025425618 hasConceptScore W3025425618C85666147 @default.
- W3025425618 hasLocation W30254256181 @default.
- W3025425618 hasOpenAccess W3025425618 @default.
- W3025425618 hasPrimaryLocation W30254256181 @default.
- W3025425618 hasRelatedWork W1243709397 @default.
- W3025425618 hasRelatedWork W1570976483 @default.
- W3025425618 hasRelatedWork W1576559744 @default.
- W3025425618 hasRelatedWork W1603961361 @default.
- W3025425618 hasRelatedWork W1965855028 @default.
- W3025425618 hasRelatedWork W1992606523 @default.
- W3025425618 hasRelatedWork W1999958161 @default.
- W3025425618 hasRelatedWork W2062383757 @default.
- W3025425618 hasRelatedWork W2410516344 @default.
- W3025425618 hasRelatedWork W2500283273 @default.
- W3025425618 hasRelatedWork W2552425423 @default.
- W3025425618 hasRelatedWork W2855561241 @default.
- W3025425618 hasRelatedWork W2940657636 @default.
- W3025425618 hasRelatedWork W2944172197 @default.
- W3025425618 hasRelatedWork W3006645393 @default.
- W3025425618 hasRelatedWork W3009132880 @default.
- W3025425618 hasRelatedWork W973876974 @default.
- W3025425618 hasRelatedWork W2932335206 @default.
- W3025425618 hasRelatedWork W3147234565 @default.
- W3025425618 hasRelatedWork W3147533701 @default.
- W3025425618 isParatext "false" @default.
- W3025425618 isRetracted "false" @default.
- W3025425618 magId "3025425618" @default.
- W3025425618 workType "dissertation" @default.