This method is for determining basic organic nitrogen inpetroleum distillates using potentiometric titration. This methodmay be applied to both clear and colored samples. The range ofquantitation for petroleum distillates is from 0.0005 to 1.0 mass-%nitrogen, while for viscous materials, such as heavy oils, therange is 0.001 to 5.00 mass-% nitrogen. This method may giveerroneous results for materials containing bases other thannitrogen compounds (e.g., caustic-washed distillates containingsodium soaps, or crude oil containing inorganic bases).

Clear or very lightly colored samples may be analyzed down to alower limit of quantitation of 0.5 mass-ppm (0.00005 mass-%) usingthe color indicator titration technique described in theAppendix.