Журнал "Макрогетероциклы"

The research purpose was studying the possibility of using some mono- and polycyclic hydrocarbons of oils on the Apsheron Peninsula as genetic indicators (biomarkers). The oil extracted from oil-contaminated soils from the
Balakhany deposit on the Absheron Peninsula was investigated. The oil contamination was analyzed by chromatography-mass spectrometry method. Low sulphur Azeri oils contain the important relict hydrocarbons such as nickel and vanadyl porphyrins. For the oil from the Balakhany deposit there was revealed the presence of homologous series of n-alkylcyclohexanes and n-alkylcyclopentanes, and the relationships between methylcyclohexane and the sum of cyclopentane hydrocarbons was studied. C₁₀ bicyclanes and their methyl homologues were determined in the investigated oil. Tricyclic saturated hydrocarbons belong to the class of naphthenes which consist of the significant part of oil hydrocarbons. Adamantane and its closest homologues (1-, 1,3- and 1,3,5-methylsubstituted adamantanes) relating to the tricyclic saturated hydrocarbons were identified in the investigated oil. In the oils of the Absheron Peninsula there were also found the tetracyclic structures with cyclopentanoperhydrophenanthrene system as the core, i.e. these compounds belong to the sterane hydrocarbons, the ratio of which for Balakhani oil is С₂₇:С₂₈:С₂₉ = 28:33:38. For oil gopans, a fragment ion m/z=191 characteristic for them was revealed. For hydrocarbons of a number of gopans of C₃₁  composition and higher, i.e. in cases when C-22 atom becomes chiral, there may be two epimers that differ in R or S configuration of C-22 chiral center. In the initial biogopans of C₃₁  composition and higher, C-22 atom has a strictly defined R configuration. It appears in a number of doublet peaks characteristic for chromatograms of mixed oil gopans. Comparison of biomarker mass fragmentograms of the investigated relict hydrocarbons, including steranes (m/z 217) and gopans (m/z 191) showed that they retain the composition almost identical to the composition of the initial oil during the experiment.