Calorimetry
       
 

Measuring heat flow

The goal of calorimetry is to measure heat flow in both physical and chemical processes. Modern calorimstry is based on the methods of differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). DSC is useful for measuring heat capacities and phase chnages of biological samples and of polymers. It can distinguish between first-order and second-order phase transitions. First-order phase transitions are the normal type with a latent heat of transition (such as melting of ice or boiling of water). Second-order phase transitions are glass transitions (e.g. from glass to liquid) or order-disorder transitions in solids and so on. DSC proviles a powerful meass to differentiate these two types of transition. ITC is useful for determining enthalpies of binding. It can also determine the fre energy of binding giving a complete thermodynamic description of the binding of ligands to proteins or DNA.