A SIMPLE AND RAPID POLARIMETRIC METHOD FOR QUANTITATIVE-DETERMINATIONOF CASTOR-OIL

A simple and rapid polarimetric method is developed for quantitation o f adulteration of castor oil in edible oils such as cottonseed, coconu t, mustard, olive, palm, peanut, rice bran, safflower, soybean, and su nflower. The method is based on the optical activity of ricinoleic aci d (12-hydroxy octadecenoic acid), a major constituent of castor oil. T here is a good correlation between optical rotation and castor oil con tent in admixtures above 5%. Highly colored and viscous oils interfere in the measurement of optical activity. The method is highly specific and cost-effective. No solvents and chemicals are required for the an alysis because no sample processing is involved in the present method.