Modelling of the thermal effects involved in the determination of heat of mixing, using an ITC operating in continuous mode

Abstract

A simplified RC model which simulates the operation mode of an isothermal titration calorimeter (ITC), when it is used in a continuous mode to determine heat of mixing, is proposed. The model takes into account several thermal effects that are evident in the mixing process and it must be identified and quantified to determine reliable values of heat of mixing. The main effects considered in the development of the model were those caused by: (i) the difference between the temperatures of the injected liquid and the mixture, (ii) the increase in heat capacity of the mixture and the thermal conductance of the couplings between the mixture and its surroundings and (iii) the changes in the power dissipated by stirring after injection. A good agreement between model and experimental results is observed.