Spektrometria masowa i analiza izotopowa biomarkerów frakcji nasyconej

GC-IRMS analysis extends and confirms (or not) the interpretation based on the results of GC-MS analyses. For example, it is very useful in determining the sedimentation environment of organic matter. GC-MS analysis of biomarkers and the results are reliable, but only GC-IRMS studies can confirm it. In this study, the origin of BNH (28,30-bisnorhopane from chemoautotrophic bacteria) and origin of higher carotenoids and their derivatives from Chlorobiaceae or Chromotiaceae bacteria were confirmed through isotopic analyzes. Biomarkers were analyzed using the GC-IRMS and EA-IRMS apparatus. The obtained chromatograms from the IRMS analyses were compared with the archival GC-MS analyses for the same samples in order to identify individual chemical compounds. In addition to the existing methodology of sample preparation for analyses, a non-standard method was also used, consisting in the separation of n-alkanes from branched hydrocarbons. The repeatability of the method was determined on the GC-IRMS and the values of δ13C for selected biomarkers from the saturated fraction were determined. It was found that samples with low biomarker content are not suitable for analysis. On the other hand, too high concentration of the analyte causes an increase of the chromatogram baseline and worse separation of the peaks, which is also a problem. For the crude oils the δ13C values were initially determined for the biomarkers of the saturated fraction from the hopanes group: bisnorhopane (BNH), oleanane, C29 norhopane, C30 hopane, moretane and the C31-C35 homohopane series. Relatively small differences in δ13C values were found between BNH/hopanes and BNH/crude oils, which suggests the same source of origin for all biomarkers (including BNH). Determining biomarkers in the aromatic fraction using the GC-IRMS method was not successful. In the future, a special methodology for preparing samples for carbon isotopic analyses of aromatic fraction will be required.

Changes in the biomarker composition of saturated fraction in late mesocatagenesis

In the paper the transformations, occurring in the distribution of n-alkanes, steranes (m/z 217) and terpanes (m/z 191) hydrocarbons with a catagenesis increase, are discussed. The results obtained in the study of the superdeep well Srednevilyuyskaya-27 (Eastern Siberia) and published works on the regions of the United States of America, Germany and India were used for that comparison. The general trends in the change of the hydrocarbons individual composition of organic matter of various genetic nature with increasing thermal maturity are shown.

Penggunaan Parameter Geokimia Isoprenoid untuk Menentukan Tingkat Kematangan Minyak Bumi (Crude Oil) Sumur Minyak Langgak Riau

In this study, crude oil samples from Distric Langgak, Riau were tested and characterized with isoprenoid parameters. Determination of thermal maturity level aims to determine the feasibility of petroleum wells to be exploited because there are many new wells of petroleum unexploited in the Riau area. Determination of maturity crude oil performed by analysis saturated fractions. Saturated fraction of the wells Langgak used to determine the maturity of crude oil based on parameters isoprenoid, n-alkane and carbon preference index were analyzed using gas chromatography-flame ionize detector (GC-FID). Based on the value Pr / Ph, Pr / n-C17, Ph / n-C18 and its CPI, the maturity level of petroleum from oil wells, Langgak levels of maturity and quality of the oil is indicated by the value of Pr / Ph (2.27), the value of Pr / n-C17 (0.57), the value of Ph / n-C18 (0.22) and the CPI (1.087) respectively.DOI :http://dx.doi.org/10.15408/jkv.v0i0.3142

320. Comparison of the growth-promoting value for rats of butter fat, of margarine fat and of vegetable oils

1. A series of experiments with rats is described in which the growth-promoting properties of butter fat have been compared with those of the solid and liquid fractions of butter fat, with margarine and with certain vegetable oils.2. The separation of butter fat into fractions containing a preponderance of glycerides of saturated or unsaturated acids was effected by means of crystallization from acetone.3. The following results were obtained by incorporating fats in liquid skim milk:(a) No differences were detected between the growth-promoting properties of butter and margarine or of butter fat and deodorized arachis oil; in the latter comparison the arachis oil was more economically used than the butter fat.(b) No differences were found between butter fat and maize oil alone or containing the solid or liquid fractions of butter fat in the approximate proportions in which they occur in the original fat. The less saturated oils, i.e. maize oil and maize oil + the liquid butter fraction, were more economically used than butter fat and its solid fraction mixed with maize oil.(c) No differences were observed between the growth-promoting values of butter fat, arachis oil, cottonseed oil or soya-bean oil. The butter fat was rather less well utilized than the less saturated oils, but the differences were not significant.(d) Poorer growth was observed with the more saturated fraction of butter fat than with the original fat or the liquid fraction.4. When butter fat, margarine fat or arachis oil was incorporated in a dry basal diet, no differences were observed in the growth-promoting value of these fats, but the arachis oil was more economically used than the other fats. This finding was not con- firmed in a second experiment of longer duration in which poorer growth was observed with the arachis-oil diet, though the economy of gains was the same with all diets.5. It is concluded from these experiments that it is unlikely that butter fat possesses superior nutritive properties to those of other fats, and that the more saturated fraction of butter fat is certainly not superior in growth-promoting value to that of the more unsaturated fraction or to more unsaturated vegetable oils.