The distribution of triaromatic dinosteroids in a range of oils and some source rock bitumens was determined by GC–MS selected ion monitoring and GC–MS-MS in order to investigate possible ambiguity in the observed distribution of isomers, including those related to maturation and alteration processes commonly affecting oil accumulations. The results confirm that the eight possible isomers for the triaromatic dinosteroids and their 28-nor equivalents (triaromatic 23,24-dimethylcholesteroids) in post-Paleozoic samples are consistently represented by six peaks on commonly used GC stationary phases, although the fifth eluting is broadened and probably represents a pair of isomers. The presence of a seventh, early eluting, triaromatic dinosteroid isomer occasionally encountered in m/z 245 mass chromatograms in the literature was not substantiated. Closely co-eluting compounds can give the seemingly misleading impression that one or two triaromatic dinosteroid isomers (including the last eluting) are present at low levels in pre-Mesozoic samples and in younger oils from dominantly higher plant sources, so care is required in inferring source age for such samples. The relative abundance and retention time pattern observed for the triaromatic dinosteroids is duplicated by their 28-nor analogues. Triaromatic dinosteroid isomer distributions vary little throughout the oil window, based on data from Norwegian North Sea oils representing a range of mean maturities. Overall abundance of the series seems to decline in a similar way to other biomarkers towards the end of the oil window. In source rock bitumen corresponding to maturities of ≤0.5% vitrinite reflectance, when diasterenes are still abundant, the second eluting triaromatic dinosteroid peak was enhanced and the fifth depleted in the limited set of samples studied (Late Jurassic marine shales from the Norwegian continental shelf). Both dinosteroid series appear particularly resistant towards biodegradation and metamorphism, with no obvious change in isomeric distributions compared to unaltered oil. As a consequence, their relative abundances, as represented by age parameters that ratio each series to their 24-ethyl counterparts, increase when alteration is severe. Lacustrine oils can be difficult to date because post-Paleozoic samples do not always contain detectable dinosteroids and, when they are present, they can vary significantly in abundance. Unambiguous age resolution at the Period level was not possible for the Triassic-Tertiary oils studied, neither could depositional environments be distinguished with confidence.

通过 GC-MS 选择离子监测和 GC-MS-MS 确定了一系列油类和一些烃源岩沥青中三芳族二元类固醇的分布，以研究观察到的异构体分布中可能存在的歧义，包括与成熟和蚀变相关的那些通常影响石油积累的过程。结果证实，后古生代样品中三芳族二烯类固醇的八种可能异构体及其 28-nor 等价物（三芳族 23,24-二甲基胆甾醇）在常用的 GC 固定相上始终由六个峰代表，尽管第五个洗脱被加宽并且可能代表一对异构体。m / z 中偶尔会遇到第七种早期洗脱的三芳族二元类固醇异构体文献中的 245 质谱图未得到证实。紧密共流出的化合物可能给人一种看似误导的印象，即在中生代之前的样品和主要来自高等植物来源的年轻油中以低水平存在一种或两种三芳族二类固醇异构体（包括最后流出的异构体），因此在推断时需要小心此类样本的来源年龄。观察到的三芳族类固醇的相对丰度和保留时间模式被它们的 28-nor 类似物重复。根据代表一系列平均成熟度的挪威北海石油的数据，三芳族二类固醇异构体分布在整个油窗口中几乎没有变化。该系列的总体丰度似乎以与其他生物标志物类似的方式在石油窗口结束时下降。在对应于 ≤ 0.5% 镜质反射率的成熟度的烃源岩沥青中，当非对映体仍然丰富时，第二个洗脱的三芳烃类类固醇峰增强，第五个在所研究的有限样品组中耗尽（来自挪威大陆架的晚侏罗世海相页岩） . 两个类固醇系列似乎都特别耐生物降解和变质，与未改变的油相比，异构体分布没有明显变化。因此，当变化严重时，它们的相对丰度（由每个系列与其 24-乙基对应物的比率）表示的年龄参数会增加。湖相油很难确定年代，因为后古生代样品并不总是含有可检测到的类固醇，而且当它们存在时，它们的丰度可能会有很大差异。