A simultaneous determination method for diamondoids and thiadiamondoids in condensate oil and its geological significance: taking condensate oil from central Tarim Basin as an example

Diamondoids and thiadiamondoids in crude oil samples have the similar diamond-like cage structures, which can reflect the thermal cracking and thermochemical sulfate reduction(TSR) effect during geological processes. Therefore, the simultaneous monitoring of diamondoids and thiadiamondoids cannot only improve the efficiency of sample analysis and the accuracy of quantitative results of thiadiamondoids, but also provide more reliable and extensive geochemical interpretation for the samples. In this paper, a simultaneous quantitative detection method of diamondoids and thiadiamondoids was proposed by the means of gas chromatography-triple quadrupole mass spectrometer (GC-MS-MS). By determining the parameters of precursor and product ions, scanning time and collision energy of the target compound, a simultaneous quantitative detection method was established for diamondoids and thiadiamondoids in condensate from the central Tarim Basin. Results showed that despite the contents of diamondoids of oils from the central Tarim Basin were different, the maturity degree on the other hand, were comparable as over mature, and some samples have experienced TSR.