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Title: The identification and quantification of steryl glucosides in precipitates from commercial biodiesel

Author
item Moreau, Robert
item Wagner, Karen
item Haas, Michael

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2008
Publication Date: 7/16/2008
Citation: Moreau, R.A., Scott, K.M., Haas, M.J. 2008. The identification and quantification of steryl glucosides in precipitates from commercial biodiesel. Journal of the American Oil Chemists' Society. 85:761-770.

Interpretive Summary: There have been several experiences of the occurrence of precipitates of solid granular materials in manufacturing facilities, transport vessels, and storage tanks containing biodiesel. Most, but not all of these cases have occurred during storage at low temperatures. We obtained samples of precipitates from several biodiesel companies and analyzed them using state-of-the art instrumentation. The analyses revealed that the major components in the precipitates were steryl glucosides (SG), common phytosterols (plant sterols) found in crude soybean oil and many other plant materials. Quantitative analysis of the precipitate samples revealed that the concentration of steryl glucosides in the samples ranged from 2-28 µg SG per mg of precipitate. The methods described in this report could be used to quantitatively analyze steryl glucosides with a common high performance liquid chromatograph equipped with an ultraviolet detector. The new knowledge about the composition of the precipitates will be very useful to biodiesel manufacturers and quality control personnel who can modify biodiesel manufacturing processes and quality checks to avoid this precipitation problem which negatively impacts users of biodiesel.

Technical Abstract: There have been several experiences of the occurrence of precipitates in manufacturing facilities, transport vessels, and storage tanks containing biodiesel. In some cases these have been formed during storage at temperatures above the cloud point of the fuel. High performance liquid chromatography (HPLC) and mass spectrometry methods were applied to field receipt samples of solids from such biodiesels. The analyses revealed that the major component in the precipitates were steryl glucosides (SG), common phytosterols (plant sterols) found in crude soybean oil and many other plant materials. Quantitative analysis of the precipitate samples revealed that the concentration of steryl glucosides in the samples ranged from 2-28 µg SG per mg of precipitate. The normal phase and reverse phase methods described in this report could be used to quantitatively analyze SG with an HPLC equipped with either an evaporative light-scattering detector or a more common UV detector operating at 205 nm.