Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS) was used for geochemical characterization of 18 oil samples from Campos Basin, Brazil. Conventional analyses were also performed on these oils (API gravity and GC-FID) and in the maltenic fraction (saturated, aromatic, and polar analysis) after asphaltene precipitation, aiming the oil screening for a rapid assessment of general characteristics. The results from principal component analysis with the biomarker parameters of source, maturity, and biodegradation obtained by GC×GC–TOFMS separated the oils into two groups, mainly explained by gammacerane content. The higher sensitivity and resolution of GC×GC–TOFMS allowed the identification of unusual compounds in oils from this basin, such as methylhopanes (whose calculated ratios allowed the oils in this work to be classified as having a marine, lacustrine, or “mixed” source, the same interpretation obtained by statistical analysis), moretanes (with results that reinforce the hypothesis of same thermal evolution for the studied samples), and short-chain steranes (C21 and C22), detected in very low concentrations in all of the samples. This study is the first to show the presence of these compounds in Campos Basin crude oils.

中文翻译：

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二维二维气相色谱/飞行时间质谱仪通过地球化学参数对坎波斯盆地原油进行探索性分析

综合二维气相色谱-飞行时间质谱（GC×GC-TOFMS）用于对来自巴西坎波斯盆地的18个油样进行地球化学表征。在沥青质沉淀后，还对这些油（API重力和GC-FID）和麦芽馏分（饱和，芳香族和极性分析）进行了常规分析，目的是筛选油以快速评估一般特性。主成分分析的结果以及通过GC×GC-TOFMS获得的生物标记物的来源，成熟度和生物降解性参数将油分为两类，主要由γ-角cer烷含量来解释。GC×GC–TOFMS具有更高的灵敏度和分辨率，因此可以鉴定出该盆地石油中的不寻常化合物，例如甲基庚烷（其计算出的比率可将这项工作中的油分类为具有海洋，湖相或“混合”源，通过统计分析获得相同的解释），更多的鞣质（其结果可强化相同热演化假说的结果）对于所研究的样品）和短链甾烷（C21和C22），在所有样品中均以极低的浓度检测到。这项研究是第一个显示坎波斯盆地原油中存在这些化合物的研究。