Triterpanes, analysis

The structures of triterpanes D (166)126 and H (167),127 from Nigerian crude oil, have been established by X-ray analysis. Dryocrassol (168), from the rhizomes of Polypodium leucotomos,12H is the C-22 epimer of neriifoliol. 

Requejo A. G. (1992) Quantitative analysis of triterpane and sterane biomarkers methodology and applications in molecular maturity studies. In Biological Markers in Sediments and Petroleum (eds. J. M. Moldowan, P. Albrecht, and R. P. Philp). Prentice Hall, Englewood Cliffs, NJ, pp. 223 -240. 

A very comprehensive analysis of hydrocarbons (linear, acyclic and cyclic - steranes, hopanes etc.- isoprenoids) carboxylic acids, aldehydes, ketones and amines of the Vale do Paraiba and Marau oil shales was made by Chicarelli (27). An extremely careful quantitative and qualitative analysis of hydrocarbons (n-, iso-and anteiso-paraffins, isoprenoids, steranes and triterpanes) and carboxylic acids of Irati oil shale was presented by Carvalhaes (28). Nooner Oro (29) also reported data on the hydrocarbons pres ent in the Irati Formation. Polycyclic aromatic hydrocarbons in I-rati were determined by Youngblood Blumer (40). 

According to the results of GC-MS analysis, the triterpane fraction consisted of two C and C g isomers, four C n isomers, three C - isomers, and one isomer. Thermodynamically stable 17crude oils and ancient sediments (8,11,12) and therefore they could be called geolipid triterpanes and may be used as diagenetic-maturation indicators. ... 

In recent several years, many EPA and ASTM methods have been modified (such as the modified EPA method 8015, 8260 and 8270 and the modified ASTM methods 3328-90, 5037-90 and 5739-95) to improve specificity and sensitivity for measuring spilled oil and petroleum products in soils and waters by environmental chemists. For example, EPA Method 8270 has been modified to increase analytical sensitivity and to expand the analyte list to include petroleum specific compounds such as the alkylated PAHs, sulfur, and nitrogen containing PAHs, and biomarker triterpane and sterane compounds. The principal modification to EPA Method 8270 is the use of the high resolution GC-MS selected ion mode (SIM) analysis that olfers increased sensitivity relative to the full scan mode. Many environmental laboratories have used the modified EPA Method 8270, combined with column cleanup and rigorous QA measures, to identify and quantify low levels of hydrocarbons. 

Almost always GC-MS has been the chosen tool for identification of alkanes from geological or living sources, and such methods in general are outlined in preceding chapters. More recently, the tandem mass-spectrometric (MS-MS) technique has been applied to the effluent from GC columns and adaptions of the standard GC-MS methods have been applied for the analysis of triterpanes and steranes (C30 compounds and the like) that often occur in petroleum and are valuable geological markers . Supercritical fluid chromatography linked to MS will undoubtedly also become a widely used technique for separation and analysis of petroleum and natural waxes, as will thermospray HPLC-MS methods. 

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