Biodiesel composition was analyzed with gas chromatography (Perkin-Elmer Clarus 500) equipped with flame ionization detector and Nukol™ column. Helium was used as carrier gas and the system operating condition was set as follows: the oven has a temperature heating rate of 10 C min 1 from 110 C to 220 C for 8 min, injector and detector temperature at 220 C and 250 C, respectively