How does ITC work?
MicroCal’s ultrasensitive ITC systems use a cell feedback network (CFB) to differentially measure and compensate for heat produced or absorbed between the sample and reference cell. Twin coin-shaped cells are mounted in a cylindrical adiabatic environment, and connect to the outside through narrow access tubes (Figure 1). A thermoelectric device measures the temperature difference between the two cells and a second device measures the temperature difference between the cells and the jacket. As chemical reactions occur in the sample cell, heat is generated or absorbed. The temperature difference between the sample and reference cells (ΔT1) is kept at a constant value (i.e. baseline) by the addition or removal of heat to the sample cell, as appropriate, using the CFB system. The integral of the power required to maintain ΔT1 = constant over time is a measure of total heat resulting from the process being studied. Figure 2 is a schematic drawing of the ITC cells and syringe.
