The reference method established by ABNT (Brazilian Association of Technical Norms) NBR 15556:2008 was used to verify the accuracy of the proposed procedure.
No significant statistical difference was found between the results obtained with the proposed and the
chosen reference procedure. The proposed procedure showed no matrix influence when recovery tests were
performed (89%–103%). The results found in this study show that the proposed procedure is a good
alternative for determining Na, K, Ca, and Mg by F AAS in biodiesel samples.