Figures 24a - 24c Illustrate the combined effects of evaporative fractionation and biodegradation. The latter is demonstrated by diminishing values of n4/i4 and n5/i5 and the pronounced "valley". Evaporative fractionation is evidenced by extreme front end "roll-over" while the valley remains distinguishable and by features of gas chromatograms which are not illustrated. Evidence beyond PVT analysis is frequently required for resolution of the effects of biodegradation and evaporative fractionation. |