Changes

===Examples of problems with internal standards===

===Examples of problems with internal standards===

[[file:oiloil-and-oilsource-rock-correlations_fig8-18.png|thumb|{{figure number|14}}Gas chromatogram of the saturated hydrocarbons from the Lufa seep oil, another seep oil from Papua New Guinea. Copyright: Murray et al. (1993); courtesy Australian Geological Survey Organization.]]

[[file:oiloil-and-oilsource-rock-correlations_fig8-18.png|thumb|{{figure number|14}}Gas chromatogram of the saturated hydrocarbons from the Lufa seep oil, another seep oil from Papua New Guinea. Copyright: Murray et al.;<ref name=Murray>Murray, A. P., R. E. Summons, J. Bradshaw, and B. Pawih, 1993, Cenozoic Ooil in Paua New Guinea--evidence from geochemical analysis of two newly discovered seeps, in G. J. Carman and Z. Carman, eds., Petroleum Exploration and Development in Papua New Guinea: Proceedings of the Second PNG Petroleum Convention, Australian Geological Survey, p. 489-498</ref> courtesy Australian Geological Survey Organization.]]

[[:file:oiloil-and-oilsource-rock-correlations_fig8-17.png|Figure 13]] shows gas chromatograms of the saturated hydrocarbons from two seep oils from Papua New Guinea. Both samples contain an internal standard that elutes just before ''n''-C₂₁. Because the left oil is biodegraded, the detector sensitivity was set very high to record the trace amounts of remaining ''n''-alkanes. Consequently, the internal standard peak is very tall. In contrast, the right oil (undegraded) shows a much smaller internal standard peak because the detector sensitivity was lower.

[[:file:oiloil-and-oilsource-rock-correlations_fig8-17.png|Figure 13]] shows gas chromatograms of the saturated hydrocarbons from two seep oils from Papua New Guinea. Both samples contain an internal standard that elutes just before ''n''-C₂₁. Because the left oil is biodegraded, the detector sensitivity was set very high to record the trace amounts of remaining ''n''-alkanes. Consequently, the internal standard peak is very tall. In contrast, the right oil (undegraded) shows a much smaller internal standard peak because the detector sensitivity was lower.