TY  - JOUR
AU  - Faraj, Musbah Abduljalil M.
AU  - Šolević-Knudsen, Tatjana
AU  - Stojanović, Ksenija A.
AU  - Pavlović-Ivković, Sonja
AU  - Nytoft, Hans Peter
AU  - Jovančićević, Branimir
PY  - 2017
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/2567
AB  - The values of parameters calculated from distribution and abundance of the selected pentacyclic terpanes in crude oils from Libya and Serbia, which were originally derived from gas chromatography-mass spectrometry (GC-MS) were compared with results of quantification based on gas chromatography-mass spectrometry-mass spectrometry (GC-MS-MS). The parameters analyzed are the most often used terpane source and maturity parameters, which were applied to a large sample set of 70 oils, originating from five oil fields. The aim of the paper was to investigate to which extent the measurements of the selected parameters by these two instrumental techniques agree and to determine the influence of differences between parameter values on geochemical interpretation. For that purpose two methods, concordance correlation coefficient and mean-difference plot were used. The obtained results indicate that calculation of C(27)18 alpha(H)-22,29,30-trisnorneohopane/(C(27)18 alpha(H)-22,29,30-trisnorneohopane +C(27)17 alpha(H)-22,29,30-trisnorhopane), C(29)18 alpha(H)-30-norneohopane/C(29)17 alpha(H) 21 beta(H)-30-norhopane and C(29)17 alpha(H)21 beta(H)-30-norhopane/ C(30)17 alpha(H)21 beta(H)-hopane ratios either by GC-MS or GC-MS-MS do not significantly influence interpretation. On the other hand, the determination of C(30)17 beta(H)21 alpha(H)-moretane/C(30)17 alpha(H)21 beta(H)-hopane ratio, gammacerane index and oleanane index by GC-MS vs. GC-MS-MS could notably affect interpretation. These differences can be explained by the co-elution and the peak overlapping in GC-MS but also by better separation, higher precision and better selectivity of the GC-MS-MS. Deviation of the almost all studied parameters from the line of equality was similar for the oils from the same oil field but some differences were observed for the oils from different oil fields. Therefore, when GC-MS-MS results are to be used in organic geochemical interpretations, a regional calibration of GC-MS vs. GC-MS-MS relationship for each petroleum system is highly recommended.
PB  - Serbian Chemical Soc, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods
VL  - 82
IS  - 11
SP  - 1315
EP  - 1331
DO  - 10.2298/JSC170419075A
ER  - 

@article{
author = "Faraj, Musbah Abduljalil M. and Šolević-Knudsen, Tatjana and Stojanović, Ksenija A. and Pavlović-Ivković, Sonja and Nytoft, Hans Peter and Jovančićević, Branimir",
year = "2017",
abstract = "The values of parameters calculated from distribution and abundance of the selected pentacyclic terpanes in crude oils from Libya and Serbia, which were originally derived from gas chromatography-mass spectrometry (GC-MS) were compared with results of quantification based on gas chromatography-mass spectrometry-mass spectrometry (GC-MS-MS). The parameters analyzed are the most often used terpane source and maturity parameters, which were applied to a large sample set of 70 oils, originating from five oil fields. The aim of the paper was to investigate to which extent the measurements of the selected parameters by these two instrumental techniques agree and to determine the influence of differences between parameter values on geochemical interpretation. For that purpose two methods, concordance correlation coefficient and mean-difference plot were used. The obtained results indicate that calculation of C(27)18 alpha(H)-22,29,30-trisnorneohopane/(C(27)18 alpha(H)-22,29,30-trisnorneohopane +C(27)17 alpha(H)-22,29,30-trisnorhopane), C(29)18 alpha(H)-30-norneohopane/C(29)17 alpha(H) 21 beta(H)-30-norhopane and C(29)17 alpha(H)21 beta(H)-30-norhopane/ C(30)17 alpha(H)21 beta(H)-hopane ratios either by GC-MS or GC-MS-MS do not significantly influence interpretation. On the other hand, the determination of C(30)17 beta(H)21 alpha(H)-moretane/C(30)17 alpha(H)21 beta(H)-hopane ratio, gammacerane index and oleanane index by GC-MS vs. GC-MS-MS could notably affect interpretation. These differences can be explained by the co-elution and the peak overlapping in GC-MS but also by better separation, higher precision and better selectivity of the GC-MS-MS. Deviation of the almost all studied parameters from the line of equality was similar for the oils from the same oil field but some differences were observed for the oils from different oil fields. Therefore, when GC-MS-MS results are to be used in organic geochemical interpretations, a regional calibration of GC-MS vs. GC-MS-MS relationship for each petroleum system is highly recommended.",
publisher = "Serbian Chemical Soc, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods",
volume = "82",
number = "11",
pages = "1315-1331",
doi = "10.2298/JSC170419075A"
}

Faraj, M. A. M., Šolević-Knudsen, T., Stojanović, K. A., Pavlović-Ivković, S., Nytoft, H. P.,& Jovančićević, B.. (2017). GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods. in Journal of the Serbian Chemical Society
Serbian Chemical Soc, Belgrade., 82(11), 1315-1331.
https://doi.org/10.2298/JSC170419075A

Faraj MAM, Šolević-Knudsen T, Stojanović KA, Pavlović-Ivković S, Nytoft HP, Jovančićević B. GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods. in Journal of the Serbian Chemical Society. 2017;82(11):1315-1331.
doi:10.2298/JSC170419075A .

Faraj, Musbah Abduljalil M., Šolević-Knudsen, Tatjana, Stojanović, Ksenija A., Pavlović-Ivković, Sonja, Nytoft, Hans Peter, Jovančićević, Branimir, "GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods" in Journal of the Serbian Chemical Society, 82, no. 11 (2017):1315-1331,
https://doi.org/10.2298/JSC170419075A . .

TY  - JOUR
AU  - Nytoft, Hans Peter
AU  - Kildahl-Andersen, Geir
AU  - Šolević-Knudsen, Tatjana
AU  - Stojanović, Ksenija A.
AU  - Rise, Frode
PY  - 2014
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/1882
AB  - A C-30 pentacyclic triterpane eluting slightly after 18 alpha(H)-oleanane in the m/z 191 mass chromatograms of Late Cretaceous/Tertiary terrigenous oils (peak "J'' in the early literature) has been isolated from a Niger Delta oil and identified using NMR spectroscopy as 3 beta-methyl-24-nor-18 alpha(H)-oleanane. The previous assignment as 18 beta(H)-oleanane is therefore partly erroneous. 3 beta-Methyl-24-nor-18 alpha(H)-oleanane affords a larger m/z 412 - gt  356 response than the oleananes and the relative contribution of 3 beta-methyl-24-nor-18 alpha(H)-oleanane to the 412 - gt  191 "oleanane peak'' can be roughly estimated from comparison of the 412 - gt  356/412 - gt  191 ratio from the oleanane peak with that of the pure compounds. 3 beta-Methyl-24-nor-18 alpha(H)-oleanane can be as abundant as 18a(H)-oleanane in oils having a high concentration of early eluting rearranged oleananes. 3 beta-Methyl-24-nor-19 alpha(H)-taraxastane was also tentatively assigned in the oils on the basis of its mass spectrum as well as its gas chromatography and high performance liquid chromatography retention times. 3 beta-Methyl-24-nor-gammacerane was tentatively assigned in a similar way in an oil containing gammacerane. All 3 beta-methyl-24-nor-triterpanes could be formed via dehydration, rearrangement and hydrogenation of triterpenoids having an OH group at C-3. (C) 2014 Elsevier Ltd. All rights reserved.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Organic Geochemistry
T1  - Compound "J'' in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18 beta(H)-oleanane
VL  - 77
SP  - 89
EP  - 95
DO  - 10.1016/j.orggeochem.2014.09.010
ER  - 

@article{
author = "Nytoft, Hans Peter and Kildahl-Andersen, Geir and Šolević-Knudsen, Tatjana and Stojanović, Ksenija A. and Rise, Frode",
year = "2014",
abstract = "A C-30 pentacyclic triterpane eluting slightly after 18 alpha(H)-oleanane in the m/z 191 mass chromatograms of Late Cretaceous/Tertiary terrigenous oils (peak "J'' in the early literature) has been isolated from a Niger Delta oil and identified using NMR spectroscopy as 3 beta-methyl-24-nor-18 alpha(H)-oleanane. The previous assignment as 18 beta(H)-oleanane is therefore partly erroneous. 3 beta-Methyl-24-nor-18 alpha(H)-oleanane affords a larger m/z 412 - gt  356 response than the oleananes and the relative contribution of 3 beta-methyl-24-nor-18 alpha(H)-oleanane to the 412 - gt  191 "oleanane peak'' can be roughly estimated from comparison of the 412 - gt  356/412 - gt  191 ratio from the oleanane peak with that of the pure compounds. 3 beta-Methyl-24-nor-18 alpha(H)-oleanane can be as abundant as 18a(H)-oleanane in oils having a high concentration of early eluting rearranged oleananes. 3 beta-Methyl-24-nor-19 alpha(H)-taraxastane was also tentatively assigned in the oils on the basis of its mass spectrum as well as its gas chromatography and high performance liquid chromatography retention times. 3 beta-Methyl-24-nor-gammacerane was tentatively assigned in a similar way in an oil containing gammacerane. All 3 beta-methyl-24-nor-triterpanes could be formed via dehydration, rearrangement and hydrogenation of triterpenoids having an OH group at C-3. (C) 2014 Elsevier Ltd. All rights reserved.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Organic Geochemistry",
title = "Compound "J'' in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18 beta(H)-oleanane",
volume = "77",
pages = "89-95",
doi = "10.1016/j.orggeochem.2014.09.010"
}

Nytoft, H. P., Kildahl-Andersen, G., Šolević-Knudsen, T., Stojanović, K. A.,& Rise, F.. (2014). Compound "J'' in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18 beta(H)-oleanane. in Organic Geochemistry
Pergamon-Elsevier Science Ltd, Oxford., 77, 89-95.
https://doi.org/10.1016/j.orggeochem.2014.09.010

Nytoft HP, Kildahl-Andersen G, Šolević-Knudsen T, Stojanović KA, Rise F. Compound "J'' in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18 beta(H)-oleanane. in Organic Geochemistry. 2014;77:89-95.
doi:10.1016/j.orggeochem.2014.09.010 .

Nytoft, Hans Peter, Kildahl-Andersen, Geir, Šolević-Knudsen, Tatjana, Stojanović, Ksenija A., Rise, Frode, "Compound "J'' in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18 beta(H)-oleanane" in Organic Geochemistry, 77 (2014):89-95,
https://doi.org/10.1016/j.orggeochem.2014.09.010 . .