Procedures for the quantitative assessment of the classes of nitrogenous compounds in light crudes and crude oil fractions are presented. Pyrrolic nitrogen levels were determined colorimetrically using p-dimethylaminobenzaldenyde, and the combined concentration of indoles, carbazoles and phenazines was obtained as their perchlorates. The total, basic and non-basic nitrogen contents of 28 Nigerian wellhead crudes and their fractions are reported in detail. The data indicate that the nitrogen contents vary with the boiling range of the fractions; the 40–180 °C fraction is free from any nitrogen content.
Fuel 08/1993; 72(8):1139-1143. DOI:10.1016/0016-2361(93)90322-S