A conductometric titration method can also be used for the determination of the base number of petroleum products. A conductivity sensor is used to measure the conductivity of the analyte which allows the endpoint to be detected. It is suitable for both new and used products having base numbers from 1 mg to 40 mg KOH/g. A sample is dissolved in a solvent mixture of Toluene/ Propan-2-ol with 0.5% deionised water.  A conductivity cell is placed in the titration vessel. The sample solution is titrated with alcoholic hydrochloric acid.