The application of thermal analysis (TA) has been extended by developing a novel method, pulse thermal analysis (PTA). The method is based on the injection of a specific amount of the gaseous reactant(s) into an inert carrier gas stream and monitoring of the changes in the mass, enthalpy and gas composition resulting from an incremental extent of the gas-solid reaction. PTA enables carrying out gas-solid reactions with a controllable reaction progress at the desired temperature. It provides the opportunity of simultaneous monitoring of changes in the composition of the gas and solid phases during the course of the reaction. PTA can also be applied for quantitative calibration of mass spectrometric signals in combined TA-MS systems. The beneficial features of the new method for investigating reduction and oxidation of solids, heterogenous catalytic reactions, and for quantitative determination of the evolved species, are illustrated using Various examples.