Improving biodiesel monoglyceride determination by ASTM method D6584-17. (1st April 2019)

• Record Type: Journal Article
• Authors: Alleman, Teresa L.; Christensen, Earl D.; Moser, Bryan R.
• Is Part Of: Fuel. Volume 241(2019)
• Page Start: 65
• Page End: 70
• Publication Date: 2019-04-01
• Subjects: Alternative feedstock -- ASTM D6584-17 -- Biodiesel -- Fuel quality -- Gas chromatography -- Monoglycerides; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.12.019
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: ASTM D6584-17 was used to quantify monoglycerides in biodiesel from novel feedstocks. The method was modified to include retention time matching for monoglycerides to better identify the correct peaks. Results show improvement in monoglyceride determination with the modified method over the method as written. Abstract: Biodiesels produced from commercial and non-traditional feedstocks were analyzed by ASTM D6584-17 for monoglyceride (monoacylglycerol, or MG) content. It was found that D6584-17 as currently written may not accurately determine MGs from conventional feedstocks due to significant differences in retention time using modern instrumentation. For biodiesel from non-traditional feedstocks, D6584-17 did not sufficiently account for MGs containing fatty acids outside of C16 and C18 species. This led to under- and over-reporting of MGs, as critical components were not accurately measured. Improvements to the method were made through a three-step process. First, a standard mixture of MGs was run to determine the retention time of individual MGs that could be present in the samples from C10 to C24. An additional analysis for the fatty acid methyl ester (FAME) profile was used to determine the major MG species present in the biodiesel samples, using the assumption that the MG profile was proportional to the FAME profile. The biodiesel samples were analyzed by D6584-17, and the MGs were identified using retention time matching, based on the major species expected from measuring the FAME profile. By combining these two methods, the accuracy of MG determination by D6584-17 was improved for biodiesels prepared from all feedstocks.