Hydrocarbon Types Analysis of Petroleum Distillates
Mass spectrometry has been used in the quantitative analysis of petroleum distillates for more than half a century. Research at U.S. oil companies, which began during WW II, led to the development of the standard ASTM mass spectrometric methods, including D 2424, D 2425, D 2786, D 2789, and D 3239. These hydrocarbon types analyses, utilizing low resolution mass spectral data, yield relative amounts of compound classes in a distillate.Methods D 2425, D 2786, and D 3239 require that the distillates be separated into saturates and aromatics using ASTM D 2549 prior to analysis.For additional information go to ASTM Methods.
Another low resolution mass spectrometric method, known as the Robinson or Amoco method, has evolved out of the ASTM methods.It is applicable to fractions boiling in a range from 199°F to 1099°F (93°C to 593°C).Four saturated hydrocarbon types, twelve aromatic hydrocarbon types, three aromatic sulfur types, and six unidentified types are reported.See reference below for further information.
Following the wide-spread availability of double focusing mass spectrometers, a high-resolution adaptation of the original mass spectrometric methods was developed. This method, known as the HC22 or Chevron method, determines eight saturated hydrocarbon types, ten aromatic hydrocarbon types and four aromatic sulfur types. It is applicable to distillates boiling in a range from 250°F to 1050°F ( 121°C to 566 °C).Refer to HC22 Method for more information.
Inquiries about having petroleum distillates analyzed by the above methods should be addressed to Ronald D. Grigsby, Ph.D.
For Further Reading
Annual Book of ASTM Standards 2010, Volume 05.01, ASTM INTERNATIONAL, West Conshohocken, PA.