Triterpanes steranes

Sterols have been identified from a 2000-year old marine sediment (283) and both steranes and pen-tacyclic triterpanes from the Green River oil-shale of Eocene age (285-... 

Optically active triterpanes have been identified from a number of crude oils (65, 81, 289). Steranes have long been known in petroleum (290) and optically active varieties identified from some crude oils (291). 

A number of hydrocarbon fractions from liquefaction products produced at GFETC from the coals studied here were investigated using selected ion profiles of the capillary GC/MS data. None of the hydrocarbon biological markers other than the acyclic alkanes already discussed were detected. There were no sesquiterpenes, sesquiter-panes, steranes, triterpanes or other cyclic terpenoids found. 

Henderson W., WoUrab V., and Eglinton G. (1969) Identification of steranes and triterpanes from a geological source by capillary gas hquid chromatography and mass spectrometry. In Advances in Organic Geochemistry 1968 (eds. P. A. Schenck and 1. Havenaar). Pergamon, London, pp. 181-207. 

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. 

Pratt L. M., Summons R. E., and Hieshima G. B. (1991) Sterane and triterpane biomarkers in the Precambrian Nonesuch Formation, North American Midcontinent Rift. Geochim. Cosmochim. Acta 55, 911—916. 

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). 

Cyclic Alkanes. In the cyclic fraction the following polycyclic isoprenoid compounds were identified (4) 27 29 steranes> methyl-C2g sterane> C 7 32 Pentacyclic triterpanes of hopane type (except C ft), anathe bicyclic tetraterpane perhydro-8-caro-tane (Table IIJ. 

Most of the geolipids so far identified in the oil shale from Aleksinac represent well known and ubiquitous constituents of sediments n-alkanes, iso- and anteiso-alkanes, aliphatic and cyclic isoprenoid alkanes including steranes, triterpanes and tetrater-panes, aromatic hydrocarbons, and aliphatic, hopanoic and aromatic acids. Moreover, several classes of compounds were identified which were also known as constituents of some ancient sediments but were not found to be ubiquitous, such as aliphatic isoprenoid ketones, aliphatic methyl ketones and the triterpenoid ketone adi-antone. 

We have investigated the variations in two groups of biomarker compounds, acyclic isoprenoids and polycycloalkanes (steranes and triterpanes), in gas chromatograms of oils produced... 

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. 

Mackenzie, A. S., Patience, R. L., Maxwell, J. R., Vandenbroucke, M. Durand, B. 1980. Molecular parameters of maturation in the Toarcian shales, Paris Basin, France. I. Changes in configuration of acyclic isoprenoid alkanes, steranes, and triterpanes. Geochimica et Cosmochimica Acta, 44, 1709-1721. 

Cyclanes from bacteria Approximately 1% of steranes and triterpanes... 

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. 

Other than rt-alkanes, pristane, phytane, and other isoprenoid alkanes that are present in abundance in unaltered oils and easily recognizable by GC and GC-MS analyses, most of the biomarker components are present in trace amounts. Among these, naphthenic hydrocarbons, including tricyclic terpanes, pentacyclic triterpanes, and steranes, have been studied most extensively because they carry more specific information on source and depositional environment than normal and isoprenoid alkanes [21]. 

Figure 3 Gas chromatography-mass spectrometric reconstructed ion chromatogram (RIC) of a typical crude oil. A RIC is equivalent to a GC flame ionization detection trace. The presence of triterpanes and steranes eluting between /j-C and n-C i are not evident due to low abundance and interference of coeluting compounds. Conditions Finnigan (San Jose, CA), 9610 gas chromatograph, Supelco (Bellefonte, PA), 30 m X 0.25 mm ID (0.1- Xm film thickness) DB-1 fused silica capillary column, temperature programmed from 120 to 310°C at 8°C/min, 1-pl injection at 50 1 split. Mass spectrometer Finnigan TSQ-46B, 70-eV electron ionization, full-scan mode from 35 to 500 Da in 1 sec cycle time.

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