Power stations with Integrated Coal Gasification Combined Cycle (IGCC) are highly efficient and flexible regarding fuel and products, e. g. power and synthesis gas. To avoid the efficiency loss in state of the art "cold" gas cleaning processes, it is necessary to develop high temperature gas cleaning processes. One of the main problems is the release of alkali species during coal gasification. This investigation was conducted to assess the potential for the reduction of alkali species by different aluminosilicate sorbents under simulated gasification conditions at a temperature of 1400 degrees C. Qualitative and quantitative analysis of the hot gas downstream the sorbent bed was carried out using molecular beam mass spectrometry (MBMS). The obtained results were used to estimate the remaining risk of fouling by means of thermodynamic calculations. (C) 2013 Elsevier Ltd. All rights reserved.