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ASTM D5291 - Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants

Significance and Use

5.1 This is the first ASTM standard covering the simultaneous determination of carbon, hydrogen, and nitrogen in petroleum products and lubricants.

5.2 Carbon, hydrogen, and particularly nitrogen analyses are useful in determining the complex nature of sample types covered by this test method. The CHN results can be used to estimate the processing and refining potentials and yields in the petrochemical industry.

5.3 The concentration of nitrogen is a measure of the presence of nitrogen containing additives. Knowledge of its concentration can be used to predict performance. Some petroleum products also contain naturally occurring nitrogen. Knowledge of hydrogen content in samples is helpful in addressing their performance characteristics. Hydrogen to carbon ratio is useful to assess the performance of upgrading processes.


1.1 These test methods cover the instrumental determination of carbon, hydrogen, and nitrogen in laboratory samples of petroleum products and lubricants. Values obtained represent the total carbon, the total hydrogen, and the total nitrogen.

1.2 These test methods are applicable to samples such as crude oils, fuel oils, additives, and residues for carbon and hydrogen and nitrogen analysis. These test methods were tested in the concentration range of at least 75 % to 87 % by mass for carbon, at least 9 % to 16 % by mass for hydrogen, and <0.1 % to 2 % by mass for nitrogen.

1.3 The nitrogen test method is not applicable to light materials or those containing <0.75 % by mass nitrogen, or both, such as gasoline, jet fuel, naphtha, diesel fuel, or chemical solvents.

1.3.1 However, using Test Method D levels of 0.1 % by mass nitrogen in lubricants could be determined.

1.4 These test methods are not recommended for the analysis of volatile materials such as gasoline, gasoline-oxygenate blends, or gasoline type aviation turbine fuels.

1.5 The results of these tests can be expressed as mass %carbon, hydrogen or nitrogen.

Extracted, with permission, from ASTM D5291-21 - Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be purchased from ASTM International,