ASTM D7591-12

Petroleum-based diesel may be blended with biodiesel. High levels of free glycerin in biodiesel can cause injector deposits (“gel effect”), as well as clogging fuel systems. High levels of unreacted glycerides can cause injector deposits and can adversely affect cold weather operation and filter plugging.

1.1 This test method covers and describes an anion exchange chromatography procedure for determining free and total glycerin content of biodiesel (B100) and blends (B0 to B20) with diesel fuel oils defined by Specification D975 Grades 1-D, 2-D, and low sulfur 1-D and 2-D and Specification D6751 (for B100 feedstocks). It is intended for the analysis of biodiesel and blend samples containing between 0.5 to 50 mg/kg glycerin.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.