Estimation of trace amounts of benzene in solvent-extracted vegetable oilsand oil seed cakes

A new method is presented for the qualitative and quantitative estimation o f trace amounts (up to 0.15 ppm) of benzene in crude as well as refined veg etable oils obtained by extraction with food grade hexane (FGH), and in the oil seed cakes left after extraction. The method involves the selection of two solvents; cyclohexanol, for thinning of viscous vegetable oil, and hep tane, for azeotroping out trace benzene as a concentrate from the resulting mixture. Benzene is then estimated in the resulting azeotrope either by UV spectroscopy or by GC-MS subject to availability and cost effectiveness of the latter. Repeatability and reproducibility of the method is within 1-3% error. This method is suitable for estimating benzene in vegetable oils an d oil seed cakes.