首页|Determining the double-bond positions of monounsaturated compounds in the alcohol fraction in seep carbonate

Determining the double-bond positions of monounsaturated compounds in the alcohol fraction in seep carbonate

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  • NSTL
  • Elsevier
The unsaturation patterns of molecular fossils are critical in distinguishing their biological precursors and diagenetic processes. However, questions regarding the determination of double-bond positions of unsaturated dialkyl glycerol ethers (DAGEs) in submarine hydrocarbon seep ecosystems remain unsolved. To address this problem, a protocol for dimethyl disulfide (DMDS) derivative analysis using gas chromatography (GC)-mass spectrometry was optimised. Herein, the double-bond positions of monounsaturated short-chain alcohols, monoalkyl glycerol ethers (MAGEs), and DAGEs in seep carbonates were analysed. Among these compounds, the double-bond positions of trimethylsilyl (TMS) derivatives of the monounsaturated DAGE-DMDS adducts were determined for the first time, with mass spectra characterized by molecular ions (M (+)(.)) and two major diagnostic ions (omega(+)& nbsp;and delta(+) ) cleaved at the double bonds. For both the MAGEs and DAGEs, the double-bond positions of the monounsaturated n-C 16:1-alkyl moieties were identified at omega 5 and omega 7. Compared to monounsaturated short-chain alcohols and MAGEs, both ionization efficiency and relative sensitivity for the TMS derivatives of DAGE-DMDS adducts were low as indicated by the high limit of detection at a signal-to-noise ratio of 3. In addition, the appropriate injection parameters and oven temperature program during GC analyses may be crucial in determining the double-bond positions within monounsaturated DAGEs. (C) 2022 Elsevier B.V. All rights reserved.

Double-bond positionMonounsaturated alkyl glycerol ether lipidsGas chromatography-mass spectrometry (GC-MS)Dimethyl disulfide (DMDS)Seep carbonateCHROMATOGRAPHY-MASS-SPECTROMETRYDIMETHYL DISULFIDE DERIVATIVESCAPILLARY GC-MSFATTY-ACIDSLIPID BIOMARKERSTABLE CARBONLOCATIONMETHANEIDENTIFICATIONDISSOCIATION

Xu, Lanfang、Guan, Hongxiang、Liu, Lei、Mao, Shengyi、Feng, Junxi、Su, Zheng、Liu, Lihua

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Chinese Acad Sci

Ocean Univ China

Guangzhou Marine Geol Survey

2022

10.1016/j.chroma.2022.463009

Journal of chromatography

Journal of chromatography

ISSN：0021-9673
年,卷(期)：2022.1672
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