This method is for determining total oxygen in liquid hydrocarbons, including synthetic paraffinic kerosene (SPK) and bio-derived green diesel fuel, by pyrolysis. The method is applicable to concentrations ranging from approximately 0.02 to 1.0 mass-%. Higher concentrations can be determined with appropriate sample dilution. The method determines the total oxygen, including organic oxygen compounds, dissolved water, and dissolved molecular oxygen. Contributions of oxygen from water and dissolved molecular oxygen must be measured using other methods (see References below) and subtracted from this result.