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, has led to the development of the standard ASTM mass-spectral methods, including D 2425, D 2786, and D 3239. These hydrocarbon types analyses yield information on relative amounts of compound classes in a distillate.
A high-resolution adaptation of the original mass-spectral methods was first published in 1967. This method (HC22) determines 18 saturate- and aromatic-hydrocarbon types and four aromatic types containing sulfur. It is applicable to olefin-free petroleum distillates boiling in a range from 250°F to 1050°F (average carbon numbers between 12 and 36) and containing less than 5 mol% total of oxygen-, nitrogen- and sulfur-containing compounds. Unlike the ASTM methods, HC22 does not require separation of the distillate into saturates and aromatics prior to analysis. Instead, auxiliary information, such as simulated distillation data (ASTM D 2887), is employed to select the proper matrices used in the calculations.
Quantitative results are presented in liquid-volume percent and in weight percent. In addition, the method provides weight percents of carbon, hydrogen, and thiophenic sulfur, the average carbon number, and the average molecular weight. Properties of the average molecule are calculated similar to those provided by the n-d-M method (ASTM D 3238). These include percents aromatic, naphthenic, and paraffinic carbon, as well as the number of aromatic and naphthenic rings.
Refer to Analysis Report for the HC22 analysis of a 500-650°F distillate.
PetroMass runs HC22 on a service basis. Turnaround time is two weeks on lots of ten samples or less.
For further information contact Ronald D. Grigsby, Ph.D.
Additional analytical services are available on request from Northrop Grumman Petroleum Technologies.
For Further Reading
Budzikiewicz, H.; Grigsby, R. D. "Mass Spectrometry and Isotopes: a Century of Research and Discussion," Mass Spec. Rev., 2006, 25, 146-157.
Annual Book of ASTM Standards 2005, Volumes 05.01 and 05.02, ASTM INTERNATIONAL, West Conshohocken, PA.
Budzikiewicz, H.; Grigsby, R. D. "Half Protons or Doubly Charged Protons? The History of Metastable Ions," J. Am. Soc. Mass Spectrom., 2004, 15, 1261-1265.
"Measuring Mass: From Positive Rays to Proteins," Michael A. Grayson, ed. © 2002 by the American Society for Mass Spectrometry. The Chemical Heritage Foundation, Philadelphia, 2002.
Teeter, R. M. "High Resolution Mass Spectrometry for Type Analysis of Complex Hydrocarbon Mixtures," Mass Spec. Rev., 1985, 4, 123-143.
Gallegos, E. J.; Green, J. W.; Lindeman, L. P.; LeTourneau, R. L.; Teeter, R. M. "Petroleum Group-Type Analysis by High Resolution Mass Spectrometry," Anal. Chem. 1967, 39, 1833-1838.
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