SI G lists the liquid-phase flowrates corresponding to 1000 ppm in the gas-phase for each mixture, and the property values that were used to calculate them. Each mixture was injected for 600 s and the LSSR signal was averaged from 300 to 600 s; SI H shows that the initial 300 s is adequate for the mixture to equilibrate with the walls of the fuel line and burner. The fuel lines were heated to 125 ℃ and above, and the burner was heated to 170 ℃. SI I shows that at these temperatures the vapor pressures of all the components were higher than their partial pressures. SI J shows that the LSSR signals of ECO, the least volatile component, increased linearly with the dopant mole fraction, which experimentally confirms that the components were not condensing in the fuel delivery system. Isooctane was included in each measurement set as an internal standard; SI K shows that the values were consistent over time and agreed with previous measurements . SI L shows that the syringe pump stepper motor performed accurately.