Popis: |
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 |