APA 6th Edition Alajbeg, A. i Kovač, T. (1994). HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum. Croatica Chemica Acta, 67 (3), 393-405. Preuzeto s https://hrcak.srce.hr/136881
MLA 8th Edition Alajbeg, Anđa i Tomislav Kovač. "HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum." Croatica Chemica Acta, vol. 67, br. 3, 1994, str. 393-405. https://hrcak.srce.hr/136881. Citirano 02.03.2021.
Chicago 17th Edition Alajbeg, Anđa i Tomislav Kovač. "HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum." Croatica Chemica Acta 67, br. 3 (1994): 393-405. https://hrcak.srce.hr/136881
Harvard Alajbeg, A., i Kovač, T. (1994). 'HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum', Croatica Chemica Acta, 67(3), str. 393-405. Preuzeto s: https://hrcak.srce.hr/136881 (Datum pristupa: 02.03.2021.)
Vancouver Alajbeg A, Kovač T. HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum. Croatica Chemica Acta [Internet]. 1994 [pristupljeno 02.03.2021.];67(3):393-405. Dostupno na: https://hrcak.srce.hr/136881
IEEE A. Alajbeg i T. Kovač, "HR GC and GC-MS Study of Steroids in Northern Croatian Petroleum", Croatica Chemica Acta, vol.67, br. 3, str. 393-405, 1994. [Online]. Dostupno na: https://hrcak.srce.hr/136881. [Citirano: 02.03.2021.]
Sažetak Since steranes might be of pharmaceutical utility, Northern Croatian petroleums were selected for a steroid study by HR GC: sample PI with a hilly elevated base of chromatograms at the heavy end (where steroids eluate) and with intensive re-alkanes; PII rich in re-alkanes with a comparatively flat heavy end; and PHI with a remarkably elevated heavy end, but poor in re-alkanes.
The fraction of saturates was studied for steranes by GC-MS, also the fraction of aromatics for MA and TA steroids. Mass spectra and mass fragmentograms m/z 217, m/z 253 and m/z 231, were used.
In 3 select samples (out of 43 petroleums), the steranes were determined in the range from norcholestanes up to re-propylcholestanes, making 3000- -9000 ppm of saturates. So, it might be considered that there are Croatian petroleum samples which contain steranes in concentrations interesting for pharmaceutical purposes. Cholestanes, ergostanes and stigmastanes are dominant while the concentrations of diasteranes are low.
Pill is the sterane richest sample. Its characteristics are low epimeri- zation of sterane skeletons, regarding H at C atoms in position 14, 17 and 20, as well as re-alkanes diminishing by biodegradation. PHI also contains the relatively highest TA steroid concentration.
The intensity proportion between TA steroids and MA steroids is highest for PII. This can be visualized by the thermal stress absorbed and it is in good agreement with the comparatively highest epimerization level.