AbstractThe periodate oxidation method was adapted for the determination of small amounts of monolycerides present in natural oils and fats. The modification consisted in enriching the monoglycerides by extraction with 90% acetic acid saturated with boric acid in order to eliminate interfering substances prior to the reaction with periodate. A multifold concentration of monoglycerides originally present was achieved. This reduced the error of the standard periodate method to a minimum. Crude oils, such as soybean, rice bran, coconut, and palm, analyzed by the modified method showed monoglyceride contents considerably lower than those obtained by direct reaction of periodate with these oils.