Title:Dissolution in Ethanol as a Sample Preparation Procedure for Determination of Metals in Biodiesel by FAAS
Volume: 10
Issue: 1
Author(s): Márcia Regina Lopes de Magalhães, Ariane Isis Barros, Adriana Paiva de Oliveira, Adriana dos Santos da Silva and Ricardo Dalla Villa
Affiliation:
Keywords:
Biodiesel, metals, flame atomic absorption spectrometry, ethanol dissolution.
Abstract: This work proposes an alternative method for determination of sodium, potassium, calcium, and magnesium in
biodiesel by flame atomic absorption spectrometry (FAAS), using dissolution in ethanol for sample preparation. The ethanolic
medium enabled the use of aqueous standards, and adjustment of the viscosity of the solutions was achieved using
samples of washed biodiesel, free of the analytes. The analytical curves showed linear correlation coefficients (r) higher
than 0.99, and the slopes obtained using different matrices indicated that the matrix had no influence on quantification of
the analytes. The instrumental limits of detection (LOD) and quantification (LOQ) for all metals were in the ranges 0.05-
0.31 mg kg-1 and 0.17-1.02 mg kg-1
,
respectively. The recovery percentages were in the range 99-114%, with relative standard
deviations (RSD) lower than 15%. The accuracy of the method was also evaluated by comparison with the Brazilian
official method, and no significant differences were observed (p=0.05). These results suggest that ethanol dissolution can
be used as an alternative method of sample preparation for determination of Na, K, Ca, and Mg in biodiesel samples by
FAAS.
