Separation of steranes and hopanes by domestic X-type molecular sieves

Abstract

Domestic 10X-type and 13X-type molecular sieves were used for the adsorption and desorption experiments of steranes and hopanes, and their stable carbon isotopic fractionation by the two kinds of molecular sieves during separation process was discussed in detail. These two kinds of molecular sieves have various adsorption effects on different types of compounds. They both have the weakest adsorption capacities for 5α, 14α, 17α-20S steranes, 5α, 14β, 17β-20R steranes and 5α, 14β, 17β-20S steranes, followed by 5α, 14α, 17α-20R steranes, β-carotane, and gammacerane. The 13X-type molecular sieve has stronger adsorption capacity for hopanes than that of the 10X-type molecular sieve, which can be used for the separation of hopanes. The 10X-type molecular sieve has stronger adsorption capacity for steranes than that of the 13X-type molecular sieve. By controlling the amount of eluent, different configuration of steranes can be further separated. The stable carbon isotopes of steranes and hopanes showed that no carbon isotopic fractionation occurred during separation process and the repeatability was very good, indicating that domestic 10X-type and 13X-type molecular sieves can be used for steranes and hopanes separation.

Keywords

• molecular sieve
• steranes
• hopanes
• compound specific carbon isotope
• biomarkers
• petroleum geochemistry