We have developed and validated a simple, quick, in-expensive method for determining the methanol or hydrocarbon content of a methanol blend fuel (a mixture of methanol and gasoline). The method exploits the insolubility of water in hydrocarbons. Briefly, 50 mL of fuel is mixed with a like amount of water and allowed to settle; the volume of the upper phase is directly correlated to the amount of hydrocarbon in the fuel. Equations and graphs are provided which translate between the hydrocarbon volume measured and the methanol content or the hydrocarbon content of the fuel. This method and the graphs and equations in this report are valid for methanol fuels made with any gasoline or virtually any hydrocarbon mixture, provided there are not oxygenates such as ethanol or MTBE present in the hydrocarbon fraction. The accuracy and precision of the method are excellent, for mixtures of dry methanol and oxygenate free gasoline.
A Simple Method to Determine the Methanol Content of Methanol Fuels
Jorgensen, S., Furey, R., and Perry, K., "A Simple Method to Determine the Methanol Content of Methanol Fuels," SAE Technical Paper 912421, 1991, doi:10.4271/912421.