Elemental analysis bitumen fractions

The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. This generalized concept has been extended to fractions derived from other carbonaceous sources, such as coal and oil shale. With this extension there has been much effort to define asphaltenes in terms of chemical structure and elemental analysis as well as by the carbonaceous source. This effort is summarized by Speight and Moschope-dis (i) in their chapter in this volume along with a good summary of the current thinking. Thus, there are petroleum asphaltenes, coal tar asphaltenes, shale oil asphaltenes, tar sands bitumen asphaltenes, and so on. In this chapter I will attempt to show how these materials are special cases of an overall concept based directly on the physical chemistry of solutions and that the idea that they have a specific chemical composition and molecular weight is incorrect even for different crude oil sources. 

Intensive research on elemental analysis has been carried out in this laboratory to overcome difficulties in determining nitrogen and sulfur in heavy fractions of petroleum or bitumens. With existing combustion techniques it was nearly impossible to obtain good overall balances for these elements when individual fractions coming from liquid chromatography were analyzed. Recoveries of 85%-95% of the quantity originally present in the... 

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