Mass spectrometry does not represent a novel physical tool in geochemical research. Petroleum chemists have made use of mass spectrometry for many years in the analysis of the components of crude oil. Such applications were concerned primarily with quantitative analytical problems, with emphasis on the determination of compound types which constitute a given petroleum sample, and the number of papers on this subject is legion. In recent years — and the developments of recent years are primarily the subject of this review — the tremendous potential of mass spectrometry for the solution of structural problems has been recognized by the organic chemical community in general, and since then rather extensive and sophisticated use has been made of the technique for structural studies on organic compounds. The widespread application to problems of organic chemistry has in turn sparked intense interest in mechanistic studies on the fragmentation processes of ionized molecules in the vapor state. Practical applications and fundamental studies combined have thus within a few years produced a substantial body of information on the nature of mass spectra of organic compounds, information which makes feasible a fruitful exploitation of mass spectrometric data for the solution of structural problems. The considerable number of volumes [1–10] addressing themselves wholly or in part to the application of mass spectrometry to problems of organic and natural products chemistry reflects the pace of progress and the scope of this field; it is recommended that these works be consulted for a thorough initiation into all phases of organic mass spectrometric research and its ramifications.

Mass Spectrometry in Organic Geochemistry

Flavones, Flavonols and their Glycosides

A number of reviews of ultraviolet and visible absorption spectroscopy have appeared in the past (Jurd, 1962; Mabry et al., 1970; Swain, 1965; Mabry, 1969; Harborne, 1963) the most comprehensive being those of Jurd (1962) and Mabry et al., (1970). The article by Jurd summarizes the work in this field up to about 1960 and gives detailed references to the original spectroscopic work carried out with flavonoids. The book by Mabry et al (1970) updates Jurd’s chapter and in addition provides a detailed catalogue of the ultraviolet (UV) spectra of 175 flavonoids together with comprehensive data on reagent induced shifts for each flavonoid. The present article includes some of the more significant aspects of the earlier reviews and in addition brings them up to date.

Ultraviolet-Visible and Proton Magnetic Resonance Spectroscopy of Flavonoids

Information on flavones, flavanones, flavanonols, flavonols, chalcones, isoflavones, biflavonoids, lignoflavonoids, and lignane glycosides and stilbenes isolated from plants of the Scutellaria L. genus was systematized and reviewed. A list of 208 phenolic compounds was given according to flavonoid type with an indication of the plant sources, structures, and physicochemical properties and citations of the original articles.

Phenolic Compounds of Plants of the Scutellaria Genus. Distribution, Structure, and Properties

Gordona sp. strain 213E (NCIMB 40816) grew in pure culture in a mineral salts medium containing fructose as a source of carbon and energy, and benzothiophene (BTH) as the sole source of sulphur. During growth a phenolic compound accumulated, as indicated by the production of a blue colour on addition of Gibb's reagent. Therefore this pathway is analogous to the dibenzothiophene (DBT) desulphurization pathway of Rhodococcus sp. strain IGTS8, in which 2-hydroxybiphenyl accumulates during growth with DBT as the sole sulphur source. Ethyl acetate extraction of the culture medium yielded the metabolites benzothiophene S-oxide (BTHO), benzothiophene S,S-dioxide (BTHO2), benzo[c][1,2]oxathiin 6-oxide (BcOTO), 2-(2′-hydroxyphenyl)ethan 1-al (HPEal) and benzofuran (BFU). The deduced pathway for BTH desulphurization is BTH → BTHO → BTHO2 → HPESi- → HPEal. HPESi- is (Z)-2-(2′-hydroxyphenyl)ethen 1-sulphinate, the stable aqueous-solution form of BcOTO. It was concluded that HPEal was the Gibb's-reagent-reactive phenolic compound which accumulated in the culture medium of strain 213E during growth, and that the presence of BFU was due to partial condensation of HPEal during the ethyl acetate extraction procedure. Gordona sp. strain 213E was unable to grow in a mineral salts medium containing fructose as a source of carbon and energy and DBT as the sole sulphur source. BTH-desulphurization-active cells (grown using BTH as sole sulphur source) were unable to desulphurize DBT. Likewise Rhodococcus sp. strain IGTS8 was unable to grow using BTH as the sole sulphur source, and DBT-desulphurization-active cells of strain IGTS8 (grown using DBT as sole sulphur source) were unable to desulphurize BTH. This absence of cross-reactivity is discussed in terms of fundamental differences in the chemistry of the DBT- and BTH-desulphurization reactions.

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Isolation of a unique benzothiophene-desulphurizing bacterium, Gordona sp. strain 213E (NCIMB 40816), and characterization of the desulphurization pathway

Studies in mass spectrometry—XV : Mass spectra of sulphoxides and sulphones. The formation of CC and CO bonds upon electron impact☆

Solvent effects in NMR Spectroscopy : Solvent shifts of methoxyl resonances in flavones induced by benzene; an aid to structure elucidation

Electron impact studies—XXII

Studies in mass spectrometry—XVIII

Studies in mass spectrometry—XX : Bond-forming reactions occurring in the fragmentation of some α,β-unsaturated esters and nitriles upon electron impact

J.H. Bowie

Papers

Studies in mass spectrometry—XV : Mass spectra of sulphoxides and sulphones. The formation of CC and CO bonds upon electron impact☆

Solvent effects in NMR Spectroscopy : Solvent shifts of methoxyl resonances in flavones induced by benzene; an aid to structure elucidation

Electron impact studies—XXII

Studies in mass spectrometry—XVIII

Studies in mass spectrometry—XX : Bond-forming reactions occurring in the fragmentation of some α,β-unsaturated esters and nitriles upon electron impact