In the characterization of catalysts (heterogeneous catalysis) a differentiation should be made between the analysis of reactive sites, which are responsible for the catalytic effect, and the carrier material, the starting material and the intermediates. On the one hand, the classical BET surface area and pore analysis play a role as well as the application of specific temperature programmed reactions and the analysis of reaction products. Further decision criterion, e.g. based on the number of analyses to be carried out, is the question whether one would like to combine as many measuring possibilities as possible in one measuring system, which can be carried out by the AUTOSORB-iQ-C/VP/TPX/MS: Physisorption, chemisorption, vapor sorption, temperature programmed reactions with connection to a mass spectrometer. However, one can also choose the separation of physisorption (BET and pore analysis) and chemisorption. During the production process, particle analyses, density determinations and other analytical methods play also a role.