Analytical methods used in the production and fuel quality assessment of biodiesel.

Biodiesel, an alternative diesel fuel derived from vegetable oil, animal fats, or waste vegetable oils, is obtained by reacting the oil or fat with an alcohol (transesterification) in the presence of a basic catalyst to give the corresponding mono-alkyl esters. Two major categories of methods besides other miscellaneous ones have been reported in the literature for assessing biodiesel fuel quality and/or monitoring the transesterification reaction by which biodiesel is produced. The two major categories comprise chromatographic and spectroscopic methods. This article considers the various methods in each category, including advantages and drawbacks, and offers suggestions on selection of appropriate methods.