Accurate knowledge of the components in the purification of biodiesel is important in achieving consistency in quality for the separation and purification process. In this paper, ternary phase diagrams were used to study the phase separation and purification of tropical almond biodiesel at temperatures of 20 degrees C, 30 degrees C and 40 degrees C. The biodiesel was produced using alkaline transesterification of the seed oil. The biodiesel was characterized using ASTM and EN standard methods. A modified cloud point titration procedure under constant temperature was used to determine the tie lines and binodal compositions. The phase mixture compositions were determined using gas chromatographic method. Distribution coefficient and selectivity analysis were performed and data accuracy, consistency and reliability were done using a first-order linear polynomial model. The result revealed free fatty acid values for the oil and the biodiesel as 0.63 and 0.23 respectively. The data quality and reliability showed a high coefficient of determination of 0.9998, adjusted coefficient of determination of 0.9887, a standard deviation of 0.0327, and a correlation coefficient of 0.8349 at the investigated temperatures. Methanol was prevalent in the glycerol phase. Ternary phase diagrams provided the visual means of estimating the distribution of the components. (C) 2020 Elsevier Ltd. All rights reserved.