Petroporphyrins: Structural elucidation and the application of HPLC fingerprinting to geochemical problems

Eglinton, G.; Hajibrahim, Saleh K.; Maxwell, James R.; Martin, John T.; Quirke, E.

doi:10.1016/0079-1946(79)90103-4

Cited by 8 publications

(6 citation statements)

References 16 publications

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“…The DPEP-type porphyrins spanned a much more narrow range of carbon numbers form C 30 -C 33 . Both these observations are in line with the previously reported nickel porphyrin distributions in gilsonite bitumen [33,37].…”

Section: Resultssupporting

confidence: 93%

“…5a-e. In the full-scan m/z range displayed, many of the peaks visible show the characteristic isotopic pattern for nickel ( 58 Ni (68%) and 60 Ni (26%)) and are observed at the m/z values expected for the radical cations of NiDPEP and Nietio type porphyrins in general [42] and specifically for gilsonite bitumen [33,37]. However, in the case of all the spectra and in particular the spectrum for band 5 (Fig.…”

Section: Resultsmentioning

confidence: 87%

“…Porphyrins from gilsonite Nickel porphyrin fractions were isolated from a sample of gilsonite bitumen through a series of column chromatography and thin-layer chromatography (TLC) separations using the procedure detailed elsewhere [37]. The end result for the present study was a series of five TLC plate porphyrin fractions, viz., bands 1-5.…”

Section: Methodsmentioning

confidence: 99%

“…Use of the commercial modified pipette tips is shown to limit the ionic species observed in the mass spectra of these porphyrin types largely, but not exclusively, to the protonated molecule. The practical utility of this electrochemical ionization approach is demonstrated using nickel geoporphyrin fractions isolated from the well-studied Gilsonite bitumen [32][33][34][35][36][37]. In addition to demonstrating the advantage of ionizing these species electrochemically, the utility of neutral loss spectra in improving the signal to background levels for discernment of the porphyrin macrocycle structural types and carbon numbers present in a sample is illustrated.…”

Section: Introductionmentioning

confidence: 99%

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Utilizing the inherent electrolysis in a chip-based nanoelectrospray emitter system to facilitate selective ionization and mass spectrometric analysis of metallo alkylporphyrins

Berkel

Kertész

2012

Anal Bioanal Chem

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A commercially available chip-based infusion nanoelectrospray ionization system was used to ionize metallo alkylporphyrins for mass spectrometric detection and structure elucidation by mass spectrometry. Different ionic forms of model compounds (nickel (II), vanadyl (II), copper (II), and cobalt (II) octaethylporphyrin) were created by using two different types of conductive pipette tips supplied with the device. These pipette tips provide the conductive contact to solution at which the electrolysis process inherent to electrospray takes places in the device. The original unmodified, bare carbon-impregnated plastic pipette tips were exploited to intentionally electrochemically oxidize (ionize) the porphyrins to form molecular radical cations for detection. Use of modified pipette tips, with a surface coating devised to inhibit analyte mass transport to the surface or slow the kinetics of the analyte electrochemical reactions, was shown to limit the ionic species observed in the mass spectra of these porphyrins largely, but not exclusively, to the protonated molecule. Under the conditions of these experiments, the effective upper potential limit for oxidation with the uncoated pipette tip was 1.1 V or less, and the coated pipette tips effectively prevented the oxidation of analytes with redox potentials greater than about 0.25 V. Product ion spectra of either molecular ionic species could be used to determine the alkyl chain length on the porphyrin macrocycle. The utility of this electrochemical ionization approach for the analysis of naturally occurring samples was demonstrated using nickel geoporphyrin fractions isolated from Gilsonite bitumen. Acquiring neutral loss spectra as a means to improve the specificity of detection in these complex natural samples was also illustrated.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Utilizing the inherent electrolysis in a chip-based nanoelectrospray emitter system to facilitate selective ionization and mass spectrometric analysis of metallo alkylporphyrins

Berkel

Kertész

2012

Anal Bioanal Chem

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“…This was later supported by mass spectrometric studies on a suite of petroporphyrins (Baker, 1966). It is now generally understood that the complexity of the porphyrin structures within a geological sample is a measure of the chemical and physical changes which have occurred in the sediment (Eglington et al, 1980(Eglington et al, , 1985a.…”

Section: Breakdown Products In Geological Samplesmentioning

confidence: 96%

The Degradation of Chlorophyll — A Biological Enigma

1987

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Summary Some 109tonnes of chlorophyll are destroyed each year on land and in the oceans. The fate of these chlorophylls is, however, largely unknown. This review describes the developmental stages at which chlorophyll breakdown occurs in aquatic and terrestrial biological systems, and the destruction arising from herbivory, disease, pollution and other physical hazards. At the cellular level, an attempt is made to separate the breakdown of chlorophyll during senescence from the many other events associated with cell destruction and death. A consideration of the more important chemical and biophysical properties of chlorophylls and their derivatives is provided, together with data on their spectral properties. The biosynthetic and biodegradative pathways of chlorophyll metabolism are, so far as is possible, described with some predictions as to the likely fate of the missing tonnes. Two types of degradation are recognized; the first involves up to five defined enzymes concerned with the early stages, the second covers the less well defined enzymic and non‐enzymic destruction of the macrocyclic structure. These degradative reactions are compared with the reactions implicated in the breakdown of other porphyrins including haems in plants and animals. A brief description is given of the occurrence of breakdown products of chlorophyll in past biomass, including those of geological significance and those in a more recent archaeological context. Finally, the economic significance of chlorophyll breakdown is considered in the context of agriculture and horticulture, veterinary and medical sciences, food colouring and cosmetic industries, and the multi‐million‐dollar attraction of autumn leaf fall to tourism.

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