title: Hydropyrolysis over a platinum catalyst as a preparative technique for the compound-specific carbon isotope ratio measurement of C27 steroids.
abstract: Compound-specific stable carbon isotope analysis by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is an important method for the determination of the (13)C/(12)C ratios of biomolecules such as steroids, for a wide range of applications. However, steroids in their natural form exhibit poor chromatographic resolution, while derivatisation adds carbon thereby corrupting the stable isotopic composition. Hydropyrolysis with a sulphided molybdenum catalyst has been shown to defunctionalise the steroids, while leaving their carbon skeleton intact, allowing for the accurate measurement of carbon isotope ratios. The presence of double bonds in unsaturated steroids such as cholesterol resulted in significant rearrangement of the products, but replacing the original catalyst system with one of platinum results in higher conversions and far greater selectivity. The improved chromatographic performance of the products should allow GC/C/IRMS to be applied to more structurally complex steroid hormones and their metabolites.
authors.affiliation: Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. william.meredith@nottingham.ac.uk
authors.forename: Will
authors.initials: W
authors.lastname: Meredith
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Gomes
authors.forename: Mick
authors.initials: M
authors.lastname: Cooper
authors.forename: Colin E
authors.initials: CE
authors.lastname: Snape
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sephton
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry*; D002384:Catalysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006358:Hot Temperature; D007553:Isotope Labeling; D008982:Molybdenum / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D013256:Steroids / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D013256:Steroids; D010984:Platinum; D008982:Molybdenum