In titration, the titrant reacts with the analyte either exothermically (gives off heat) or endothermically (absorbs heat). The Thermoprobe measures the temperature change during titration. When all of the analyte has reacted with the titrant, the temperature of the solution will change, and the endpoint of the titration is indicated by an inflection in the temperature curve. Catalytically enhanced titrations using paraformaldehyde as catalyst are based on the endothermic hydrolysis of the paraformaldehyde in the presence of excess hydroxide ions. Edible oils are dissolved in a mixture of toluene and 2-propanol (1:1) and titrated with standardized TBAH (0.01 mol/L) in 2-propanol to a catalytically enhanced endpoint.