SSITKAA addresses the intrinsic kinetics of catalytic reactions by analysis of surface species and their residence times. The technique can decouple the effect of the concentration of intermediates and site reactivity on the catalytic activity. SSITKA is usually carried out close to atmospheric pressure, while also allowing for high-pressure experiments.

A SSITKA experiment involves an abrupt switch from a regular to the corresponding isotopically labelled feed stream with identical flow and pressure. Steady state is maintained during the whole experiment, provided that no isotope effect occurs. The transient response of the product is recorded by a mass spectrometer and contains the kinetic information.

The setup is custom-built and enables SSITKA experiments on solid materials in a plug flow fixed bed reactor for gas phase catalysis using:

Gas lines are heated and the catalyst bed (plug flow reactor) can reach > 900 °C. The reactor can be operated maximally at 25 bar overpressure. A high-pressure compatible MS detection system provides unique access to high pressure SSITKA experiments.