Gas chromatographic analysis of free steroids in biodiesel

This study aimed to extract, characterize and quantify free steroids present on various types of methyl biodiesel produced in the laboratory from different raw materials and a special type of commercial biodiesel. Steroid extraction was performed by sample saponification followed by solvent extraction of insaponificable. Steroid characterization was obtained by gas chromatograph equipped with a flame ionization detector (GC-FID) and by gas chromatograph coupled with a mass spectrometer (GC–MS); steroid quantification was performed by GC-FID. Several different free steroids found present in the biodiesel types were analyzed; some of them were identified as exclusive to certain biodiesel types. It was possible, based on the present free steroid profile analysis methodology, to identify the origin of a commercial biodiesel. Analyses had show that steroid content in biodiesel types ranged from 610 mg kg−1 in the babassu biodiesel to 3250 mg kg−1 in the crambe biodiesel.