2.6. Fatty acids methyl esters analysis The fatty acid composition of the biodiesel samples was performed in a Shimadzu GC-2010 gas chromatograph (GC) equipped with a hydrogen flame ionization detector. Fatty acid methyl esters (FAME) for analysis were prepared by the method proposed by Hartmann and Lago [10].The GC conditions were as follows: column RTX-WAX (fused silica, 0.25 mm 30 m 0.25 lm), a column temperature program that specified a injector temperature of 230 C, a split ratio of 1:100, an oven temperature program of 130–240 C(4 C/min), a detector temperature of 250 C, use of H2 as a carrier gas and velocity in the column was controlled at 35 cm/s.