Abstract A homologous series of tetracyclic polyprenanes from C24 to C41 was identified in crude oils from Espirito Santo Basin (Brazil) by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOFMS) and gas chromatography–tandem mass spectrometry (GC–MS-MS) analyses. These products were separately characterized by elution order in first- and second-dimension retention times (1tR and 2tR, respectively), time-of-flight mass spectra (TOFMS), MRM chromatograms, product ion spectra including diagnostic ions at m/z 191, m/z 259 and m/z 149 + 14n (n = 0–17), the latter a key mass fragment for the evaluation of side chain extension at the C-18 position in tetracyclic polyprenoids. The tetracyclic compounds were thus identified as scalarane-like structures related to abundant C30 tetracyclic polyprenoids, an important indicator of input from fresh to brackish water paleoenvironments.

中文翻译：

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原油中扩展四环聚异戊二烯系列的存在

摘要 通过综合二维气相色谱-飞行时间质谱 (GC×GC-TOFMS) 和气相色谱-串联质谱法在来自巴西圣埃斯皮里图盆地的原油中鉴定了 C24 至 C41 的同源系列四环聚戊二烯。质谱 (GC-MS-MS) 分析。这些产品分别通过第一维和第二维保留时间（分别为 1tR 和 2tR）的洗脱顺序、飞行时间质谱 (TOFMS)、MRM 色谱图、产物离子谱（包括 m/z 191 处的诊断离子）进行表征, m/z 259 和 m/z 149 + 14n (n = 0–17)，后者是评估四环聚异戊二烯 C-18 位侧链延伸的关键质量片段。因此，四环化合物被鉴定为与丰富的 C30 四环聚异戊二烯相关的类似标量的结构，