No. Sample The threshold concentration of heptane,% wt. (for 0.1g/l asphaltenes/toluenesolutions) The threshold concentration of heptane,% wt. (for 5g/l asphaltenes/toluene solutions) 1 Initial asphaltenes (top part) 46 40 2 Initial asphaltenes (bottom part) 48 46.5 3 Asphaltenes A1 (top part) 43 25 4 Asphaltenes A1 (bottom part) 28 20.2 5 Asphaltenes A2 (top part) - 69 6 Asphaltenes A2 (bottom part) - 55

Table 1: The threshold concentrations of heptane for 0.1g/l and 5g/l solutions of asphaltenes and their fractions in toluene.