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Diamondoid characterization in condensate by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry: The Junggar Basin of Northwest China.

Li S, Hu S, Cao J, Wu M, Zhang D - Int J Mol Sci (2012)

Bottom Line: However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil.It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)).The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education, Wuhan 430074, China; E-Mails: hushzh@cug.edu.cn (S.H.); zdm2007@cug.edu.cn (D.Z.).

ABSTRACT
Diamondoids in crude oil are useful for assessing the maturity of oil in high maturation. However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil. In this paper, we use comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) to study the compounds in condensates from the Junggar Basin of northwest China and address their geological and geochemical applications. GC×GC-TOFMS improves the resolution and separation efficiency of the compounds. It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)). A reversed-phase column system improves the separation capabilities over the normal phase column system. The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%.

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Related in: MedlinePlus

Mass spectra of 1,3,4-trimethyl-adamantane and No. 15A peak in Figure 1a.
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f2-ijms-13-11399: Mass spectra of 1,3,4-trimethyl-adamantane and No. 15A peak in Figure 1a.

Mentions: In the trimethyl-adamantanes, there is a compound that has rarely been detected in conventional GC-MS analysis, which is located near the No. 15 peak (Figure 1a). It cannot be accurately named due to the lack of standard spectra and material so far. Since its chromatogram is very similar to the No. 15 peak (Figure 1a), we tentatively named it as the No. 15A peak. Its mass spectra is very similar to 1, 3, 4-trimethyl-adamantanes, with m/z 163 being the characteristic peak and molecular weight being 178 (Figure 2). Thus, it most likely belongs to the trimethyl-adamantane group of compounds. Furthermore, according to the peak order of multi-methyl-naphthalene and multi-methyl-phenanthrene, the peak of the compound in isomers shows a backward trend when the replacing position of multi-methyl becomes centralized. Therefore, we propose that the compound may be 1, 2, 3- or 2, 3, 4-trimethyladamantanes.


Diamondoid characterization in condensate by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry: The Junggar Basin of Northwest China.

Li S, Hu S, Cao J, Wu M, Zhang D - Int J Mol Sci (2012)

Mass spectra of 1,3,4-trimethyl-adamantane and No. 15A peak in Figure 1a.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472753&req=5

f2-ijms-13-11399: Mass spectra of 1,3,4-trimethyl-adamantane and No. 15A peak in Figure 1a.
Mentions: In the trimethyl-adamantanes, there is a compound that has rarely been detected in conventional GC-MS analysis, which is located near the No. 15 peak (Figure 1a). It cannot be accurately named due to the lack of standard spectra and material so far. Since its chromatogram is very similar to the No. 15 peak (Figure 1a), we tentatively named it as the No. 15A peak. Its mass spectra is very similar to 1, 3, 4-trimethyl-adamantanes, with m/z 163 being the characteristic peak and molecular weight being 178 (Figure 2). Thus, it most likely belongs to the trimethyl-adamantane group of compounds. Furthermore, according to the peak order of multi-methyl-naphthalene and multi-methyl-phenanthrene, the peak of the compound in isomers shows a backward trend when the replacing position of multi-methyl becomes centralized. Therefore, we propose that the compound may be 1, 2, 3- or 2, 3, 4-trimethyladamantanes.

Bottom Line: However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil.It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)).The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education, Wuhan 430074, China; E-Mails: hushzh@cug.edu.cn (S.H.); zdm2007@cug.edu.cn (D.Z.).

ABSTRACT
Diamondoids in crude oil are useful for assessing the maturity of oil in high maturation. However, they are very difficult to separate and accurately quantify by conventional geochemical methods due to their low abundance in oil. In this paper, we use comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) to study the compounds in condensates from the Junggar Basin of northwest China and address their geological and geochemical applications. GC×GC-TOFMS improves the resolution and separation efficiency of the compounds. It not only separates the compounds that coelute in conventional GC-MS (e.g., 4, 8-dimethyl-diamantane and trimethyl-diamantane) but also allows the identification of compounds that were not previously detected (e.g., trimethyl-diamantane (15A)). A reversed-phase column system improves the separation capabilities over the normal phase column system. The diamondoid indexes indicate that a representative condensate from Well DX 10 is highly mature with equivalent Ro being approximately 1.5%.

Show MeSH
Related in: MedlinePlus