Unlike the free biomarkers, which can be routinely recovered via solvent extraction, the bound biomarkers are covalently linked to the kerogen or asphaltene macrostructures and are more resistant to secondary alteration processes. Although similarities have been identified between these two types of biomarkers using different techniques, it remains unclear how the kerogen- and asphaltene-bound biomarkers are complicatedly corelated with their free counterparts, thus limiting the applications of bound biomarkers in geoscience research. In this study, the characteristics of free biomarkers recovered from shale samples, from 10 sedimentary basin around the world, and petroleum samples, from the North Sea, have been systematically compared with their kerogen- and asphaltene-bound biomarkers, which were released by the newly developed Microscale Sealed Vessel Catalytic Hydrogenation (MSSV-Hy) method. Although the kerogen-bound biomarkers are characterized by the absence of rearranged biomarkers (e.g., Ts and diasteranes) and elevated C₂₉/C₃₀ hopane ratios, many key source-related parameters show strong positive correlations between free and bound fractions, including the steranes/hopane, C₂₇/C₂₉ sterane, C₃₀/C₂₉ sterane, C₂₉/C₃₀ hopane (αβ + βα), C₃₅/C₃₄ homohopanes and C₂₄ tetracyclic terpane/C₂₆ tricyclic terpane ratios. These results suggest that bound biomarkers can reveal critical information about deposits and organic matter precursors of source rocks. Thermal maturity indicators, such as C₂₉ sterane ββ/(αα + ββ), C₂₉ sterane S/(S + R), C₃₁ hopane S/R, and Tβ/Tm ratios, also display excellent correlations between the free and bound counterparts in the source rocks. Although the correlations are not 1:1, empirical formulae, which are based on the correlations between free and bound biomarkers, can be used to calibrate bound biomarkers into values that can be directly compared to routine free biomarkers. Importantly, asphaltene-bound biomarkers of North Sea samples exhibit similar characteristics to kerogen-bound biomarkers, and the conversion between free and bound biomarkers of the source rock and reservoir samples is the same. In summary, the bound biomarkers are found highly effective in determining the organic facies, lithology, and thermal maturity of the parent kerogen and/or asphaltene, and, thus, have a great potential to be widely used in geoscience research when information from free biomarkers is hampered by oil mixing, contamination or biodegradation.

与可以通过溶剂提取常规回收的游离生物标志物不同，结合的生物标志物与干酪根或沥青质宏观结构共价连接，并且更能抵抗二次改变过程。尽管已经使用不同的技术确定了这两种类型的生物标志物之间的相似之处，但仍不清楚与干酪根和沥青质结合的生物标志物如何与其自由对应物复杂地关联，从而限制了结合生物标志物在地球科学研究中的应用。在这项研究中，从全球 10 个沉积盆地的页岩样品和北海的石油样品中回收的游离生物标志物的特征与其干酪根和沥青质结合的生物标志物进行了系统比较，它们是通过新开发的微型密封容器催化加氢（MSSV-Hy）方法释放的。尽管与干酪根结合的生物标志物的特征是不存在重排的生物标志物（例如，Ts 和二甾烷）和升高的 C₂₉ /C ₃₀藿烷比率，许多与源相关的关键参数显示出游离和结合部分之间的强正相关，包括甾烷/藿烷、C ₂₇ /C ₂₉甾烷、 C ₃₀ /C ₂₉甾烷、 C ₂₉ /C ₃₀藿烷（ αβ + βα)、C ₃₅ /C ₃₄高藿烷和 C ₂₄四环萜烷/C ₂₆三环萜烷的比率。这些结果表明，结合的生物标志物可以揭示有关沉积物和烃源岩有机质前体的关键信息。热成熟度指标，如C ₂₉甾烷ββ/(αα + ββ)、C ₂₉甾烷 S/(S + R), C ₃₁藿烷 S/R 和 Tβ/Tm 比率也显示了烃源岩中游离和结合对应物之间的良好相关性。尽管相关性不是 1:1，但基于游离和结合生物标志物之间相关性的经验公式可用于将结合生物标志物校准为可直接与常规游离生物标志物比较的值。重要的是，北海样品的沥青质结合生物标志物表现出与干酪根结合生物标志物相似的特征，并且源岩和储层样品的游离和结合生物标志物之间的转换是相同的。总之，发现结合的生物标志物在确定母体干酪根和/或沥青质的有机相、岩性和热成熟度方面非常有效，因此，