In thermometric titrations, a constant addition rate of titrant equates to a constant amount of heat being given out or consumed, and hence a more or less constant temperature change up to the endpoint. In a titration, the titrant reacts with the analyte in the sample either exothermically or endothermically. The thermoprobe measures the temperature of the titrating solution. When all of the analyte in the sample has reacted with the titrant, the temperature of the solution will change, and the endpoint of the titration is revealed by an inflection in the temperature curve.
An appropriate aliquot of the sample is pipetted directly into the titration vessel, and isobutyl vinyl ether and toluene solvent are added. The solution is then titrated with trifluoro methane sulfonic acid (TFMSA) to a single thermometric endpoint.