Volatility is an important property in fuels research because it can significantly affect performance and because it is highly sensitive to changes in the composition of a mixture. In the laboratory, volatility is measured as a distillation curve. Difficulty arises when the fluid to be measured is non-homogeneous; that is, it has more than one liquid phase. Using the advanced distillation curve (ADC) method, we analyzed two such fluids, crude pyrolysis oils containing significant water that formed an aqueous phase separate from the organic phase. In this communication, we present a data analysis method that compensates for non-homogeneity in these samples and enables us to compare the organic phase to the experience base of previously measured petroleum and pyrolysis oils. Published by Elsevier Ltd.