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Reference Materials and Standards for Fossil Fuels, Electric Utility Emissions, and Coal Combustion By-Products


National Institute of Standards and Technology (NIST) fossil fuel Standard Reference Materials (SRMs) continue to be in high demand by the petroleum industry and the fossil fuel-based electric utility industries. In the past, the measurement of sulfur in fuels and combustion systems has received principal attention, but mercury emissions are now attracting regulatory interest because of the potential risk to human health. Measurements of carbon will also become more important as trading systems come into effect to combat climate change effects from the release of carbon dioxide into the atmosphere. The generation of large quantities of coal combustion by-products, having significant levels of unwanted contaminants, also represents a significant measurement challenge.


Photograph of a labeled mylar envelop and labeled amber bottle containing SRM 2683c Bituminous Coal.

SRM 2683c Bituminous Coal (Nominal Mass Fraction 2 % Sulfur) 

Credit: Lane Sander

Until newer sustainable energy technologies can be deployed, fossil fuels will remain the principal source of energy for the developed world. Coal, oil, and natural gas account for over 85 % of the energy consumed by the U.S. Along with the need for more efficient utilization of these resources, there is a need for the environmental management of electric utility combustion emissions and waste products, and pollutant emissions from vehicles using liquid fuels. Sulfur, mercury, and carbon are (or will likely be) subject to environmental regulations. Management of energy production from the specification of fossil fuel raw materials to the release of environmental pollutants from combustion processes, together with risk assessment of bulk waste products, such as fly-ash and flue gas de-sulfurization (FGD) gypsum, will require accurate analytical measurements, and there will undoubtedly be increasing demand for relevant reference materials to support the emerging needs of these markets.

Major Accomplishments

  • Approximately 60 fossil fuel-related SRMs are available to support the needs of the energy, electric utility, and transportation fuel sectors.     
  • A gravimetric mixing tool for producing intermediate certified values for sulfur in fossil fuel SRMs has been developed. 
  • New high-accuracy isotope dilution mass spectrometric analytical methods have been developed for the measurement of mercury and chlorine in complex matrix materials. All of the coal SRMs are now certified for mercury, and three of them for chlorine.     
  • A certification system has been implemented to provide traceability infrastructure for electric utility mercury emissions monitoring.

Additional Technical Details

The fossil fuel SRM program is now 40 years old, and the current inventory of fossil fuel reference materials includes coals, cokes, residual fuel oils, distillates and gasolines. Many of these have been certified, and will continue to be certified, using high-accuracy methods such as isotope dilution mass spectrometry. A challenge in recent years has been the assignment of accurate mercury concentrations in bituminous and sub-bituminous coals and at lower levels in unrefined crude oil and diesel fuel. This has been achieved through the development of a method using high-pressure Carius digestion coupled with isotope dilution mass spectrometry. Similarly, new methods for the determination of chlorine in coals using instrumental neutron activation and thermal ionization mass spectrometry have resulted in the provision of certified values for this element in several of the coal SRMs. In anticipation of demand for standards to support carbon accounting activities, new methods for the high-accuracy measurement of carbon in new and existing fossil fuel SRMs will be a priority in the near future. New instrumentation consisting of multi-collector inductively coupled plasma mass spectrometry has recently been acquired, and this will be assessed for the measurement of carbon in fossil fuels by isotope dilution. 

Additional information on relevant reference materials is linked below.   

1619b Sulfur in Residual Fuel Oil (Nominal Mass Fraction 0.7 %) 

1622e Sulfur in Residual Fuel Oil (Nominal Mass Fraction 2 %) 

1623d Sulfur in Residual Fuel Oil (Nominal Mass Fraction 0.2 %) 

1633c Trace Elements in Coal Fly Ash  

1634c Trace Elements in Fuel Oil 

1635a Trace Elements in Coal (Subbitumimous) 

2298 Sulfur in Gasoline (High-Octane) 

2299 Sulfur in Gasoline (Reformulated) 

2429 Flue Gas Desulfurization Gypsum  

2682c Subbituminous Coal (Nominal Mass Fraction 0. 5 % Sulfur) 

2683c Bituminous Coal (Nominal Mass Fraction 2 % Sulfur) 

2684c Bituminous Coal (Nominal Mass Fraction 3 % Sulfur) 

2685c Bituminous Coal (Nominal Mass Fraction 5 % Sulfur) 

2689 Coal Fly Ash  

2690 Coal Fly Ash  

2691 Coal Fly Ash  

2692c Bituminous Coal (Nominal Mass Fraction 1 % Sulfur) 

2693 Bituminous Coal (Nominal Mass Fraction 0.5 % Sulfur) 

2717a Sulfur in Residual Fuel Oil (Nominal Mass Fraction 3%) 

2718a Green Petroleum Coke  

2719 Calcined Petroleum Coke  

2720 Sulfur in Di-n-Butyl-Sulfide 

2721 Crude Oil (Light-Sour) 

2722 Crude Oil (Heavy-Sweet) 

2723b Sulfur in Diesel Fuel Oil 

2770 Sulfur in Diesel Fuel Oil 

2775 Sulfur in Foundry Coke  

2776 Sulfur in Furnace Coke  

8499 Trace Elements in Coal (Bituminous) 

8505 Vanadium in Crude Oil 



1. Long, S. E., Norris, J. E., Carney, J., Ryan, J. V., Mitchell, G. D., and Dorko, W. D., "Traceability of the output concentration of mercury vapor generators," Atmospheric Pollution Research, 11, (2020). 

2. Ramisetti, S. R., Ona-Ruales, J. O., Wise, S. A., Amin, S., and Sharma, A. K., "An Efficient Synthesis of Dibenzo[a,l]tetracene and Dibenzo[a,j]tetracene and Their Identification in a Coal Tar Extract," Polycyclic Aromatic Compounds, 40, 88-98 (2020). 

3. Hayes, H. V., Wilson, W. B., Sander, L. C., Wise, S. A., and Campiglia, A. D., "Determination of PAHs in Combustion-Related Samples via Multidimensional Chromatographic Methods," Lc Gc North America, 37, 872-877 (2019). 

4. Wilson, W. B., Hayes, H. V., Campiglia, A. D., and Wise, S. A., "Qualitative characterization of three combustion-related standard reference materials for polycyclic aromatic sulfur heterocycles and their alkyl-substituted derivatives via normal-phase liquid chromatography and gas chromatography/mass spectrometry," Analytical and Bioanalytical Chemistry, 410, 4177-4188 (2018). 

5. Wilson, W. B., Hayes, H. V., Sander, L. C., Campiglia, A. D., and Wise, S. A., "Qualitative characterization of SRM 1597a coal tar for polycyclic aromatic hydrocarbons and methyl-substituted derivatives via normal-phase liquid chromatography and gas chromatography/mass spectrometry," Analytical and Bioanalytical Chemistry, 409, 5171-5183 (2017). 

6. Christopher, S. J. and Vetter, T. W., "Application of Microwave-Induced Combustion and Isotope Dilution Strategies for Quantification of Sulfur in Coals via Sector-Field Inductively Coupled Plasma Mass Spectrometry," Analytical Chemistry, 88, 4635-4643 (2016). 

7. Ona-Ruales, J. O., Ruiz-Morales, Y., and Wise, S. A., "Identification and quantification of seven fused aromatic rings C26H14 pen-condensed benzenoid polycyclic aromatic hydrocarbons in a complex mixture of polycyclic aromatic hydrocarbons from coal tar," Journal of Chromatography A, 1442, 83-93 (2016). 

8. Ona-Ruales, J. O., Sharma, A. K., and Wise, S. A., "Identification and quantification of six-ring C26H16 cata-condensed polycyclic aromatic hydrocarbons in a complex mixture of polycyclic aromatic hydrocarbons from coal tar," Analytical and Bioanalytical Chemistry, 407, 9165-9176 (2015). 

9. Molloy, J. L., MacDonald, B. S., and Kelly, W. R., "Software Package To Facilitate the Preparation of Intermediate-Range Fossil Fuel Standards from Certified Reference Materials," Energy & Fuels, 24, 3560-3564 (2010). 

10. Wise, S. A., Poster, D. L., Leigh, S. D., Rimmer, C. A., Mossner, S., Schubert, P., Sander, L. C., and Schantz, M. M., "Polycyclic aromatic hydrocarbons (PAHs) in a coal tar standard reference material-SRM 1597a updated," Analytical and Bioanalytical Chemistry, 398, 717-728 (2010). 

11. MacDonald, B. S., Molloy, J. L., Leigh, S. D., Kelly, W. R., and Rukhin, A. L., "A Statistic that Identifies Errant Standard Preparation and Instrument Nonlinearity Demonstrated with Mercury Standards Prepared by Blending NIST Fossil Fuel CRMs of Similar Matrices,"  Energy & Fuels, 23, 6048-6054 (2009). 

12. Poster, D. L., Kucklick, J. R., Schantz, M. M., Porter, B. J., Sander, L. C., and Wise, S. A., "New developments in Standard Reference Materials (SRMs) for environmental forensics," Environmental Forensics, 8, 181-191 (2007). 

13. Wise, S. A., Poster, D. L., Kucklick, J. R., Keller, J. M., VanderPol, S. S., Sander, L. C., and Schantz, M. M., "Standard reference materials (SRMs) for determination of organic contaminants in environmental samples," Analytical and Bioanalytical Chemistry, 386, 1153-1190 (2006). 

14. Schubert, P., Schantz, M. M., Sander, L. C., and Wise, S. A., "Determination of polycyclic aromatic hydrocarbons with molecular weight 300 and 302 in environmental-matrix standard reference materials by gas chromatography/mass spectrometry," Analytical Chemistry, 75, 234-246 (2003). 

15. Reddy, C. M., Pearson, A., Xu, L., McNichol, A. P., Benner, B. A., Wise, S. A., Klouda, G. A., Currie, L. A., and Eglinton, T. I., "Radiocarbon as a tool to apportion the sources of polycyclic aromatic hydrocarbons and black carbon in environmental samples," Environ. Sci. Technol., 36, 1774-1782 (2002). 

16. Wise, S. A., "Standard Reference Materials (SRMs) for the determination of polycyclic aromatic compounds - Twenty years of progress," Polycyclic Aromatic Compounds, 22, 197-230 (2002). 

17. Turk, G. C., Yu, L. L., Salit, M. L., and Guthrie, W. F., "Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs," Fresenius Journal of Analytical Chemistry, 370, 259-263 (2001). 

18. Winchester, M. R., Kelly, W. R., Mann, J. L., Guthrie, W. F., MacDonald, B. S., and Turk, G. C., "An alternative method for the certification of the sulfur mass fraction in coal Standard Reference Materials," Fresenius Journal of Analytical Chemistry, 370, 234-240 (2001). 

19. Yu, L. L., Kelly, W. R., Fassett, J. D., and Vocke, R. D., "Determination of sulfur in fossil fuels by isotope dilution electrothermal vaporization inductively coupled plasma mass spectrometry," Journal of Analytical Atomic Spectrometry, 16, 140-145 (2001). 

20. Poster, D. L., De Alda, M. J. L., Wise, S. A., Chuang, J. C., and Mumford, J. L., "Determination of PAHs in combustion-related samples and in SRM 1597, complex mixture of PAHs from coal tar," Polycyclic Aromatic Compounds, 20, 79-95 (2000). 

21. Mossner, S. G. and Wise, S. A., "Determination of polycyclic aromatic sulfur heterocycles in fossil fuel-related samples," Analytical Chemistry, 71, 58-69 (1999). 

22. Chuang, J. C., Wise, S. A., Cao, S., and Mumford, J. L., "Chemical Characterization of Mutagenic Fractions of Particles from Indoor Coal Combustion - A Study of Lung-Cancer in Xuan-Wei, China," Environ. Sci. Technol., 26, 999-1004 (1992). 

23. May, W. E., Benner, B. A., Wise, S. A., Schuetzle, D., and Lewtas, J., "Standard Reference Materials for Chemical and Biological Studies of Complex Environmental-Samples," Mutation Research, 276, 11-22 (1992). 

24. Garrigues, P., Bellocq, J., and Wise, S. A., "Determination of Methylbenzo[A]Pyrene Isomers in A Coal-Tar Standard Reference Material Using Liquid-Chromatography and Shpolskii Spectrometry," Fresenius Journal of Analytical Chemistry, 336, 106-110 (1990). 

25. Wise, S. A., Benner, B. A., Byrd, G. D., Chesler, S. N., Rebbert, R. E., and Schantz, M. M., "Determination of Polycyclic Aromatic-Hydrocarbons in A Coal-Tar Standard Reference Material," Analytical Chemistry, 60, 887-894 (1988). 

Created December 30, 2008, Updated November 6, 2023