International. ASTM International members recently reviewed a key test method (D1613) that has been used to measure the acidity of fuel ethanol and denatured fuel ethanol, including ethanol used for automotive gasoline blends.
D1613 is formally known as the standard test method for acidity in volatile solvents and chemical intermediates used in paint, varnish, lacquer and related products. Reviewed by ASTM International Committee on Paint and Coatings, Materials and Related Applications (D01)
By including a new "nitrogen purge" as part of the testing method, a lab can help ensure that carbon dioxide is removed. According to ASTM International member Shon Van Hulzen, the presence of carbon dioxide is known to produce incorrectly high acidity values, which can affect the product's ability to meet the specifications of denatured fuel ethanol used in spark-ignition engines (D4806).
"Historically, the test method did not specifically require a purge step," Van Hulzen said. "But if samples of denatured fuel ethanol are not purged, it can often lead to erroneously high acidity results due to the entrained carbon dioxide."
Notably, this purge is already required in the test method for acidity in ethanol and ethanol titration mixtures (D7795).
D1613 is formally known as the "standard test method for acidity in volatile solvents and chemical intermediates used in paint, varnish, lacquer and related products. Reviewed by ASTM International Committee on Paint and Coatings, Materials and Related Applications (D01)
