A vacuum analytical method for the determination of oxygen in organic compounds was developed. Several milligrams (usually 3 to 5 mg) of the organic to be analyzed are sealed in an evacuated quartz bomb along with 2.5 to 3.5 mg of an organic reducing agent. Next the bomb is fired at 1050-- 1055 deg C for 30 minutes or longer. At the end of the heating period the bomb temperature is rapidly lowered from 1055 deg C to <650 deg C. As a last step the gaseous products are removed from the bomb and the volumes of CO and H/sub 2/ are determined. From these values the percentage of oxygen can be calculated providing an appropriate blank is obtained. Compounds containing carbon, hydrogen, nitrogen, sulfur, iodine, and chlorine have been successfully analyzed for oxygen. Organic compounds containing fluorine cannot be analyzed for oxygen by this method, because fluorine reacts with quartz to form oxygen and silicon tetrafluoride. (auth)