New plug-flow cells suitable for the X-ray absorption spectroscopy (XAS) study of heterogeneous catalysts by transmission and fluorescence detection modes are described. These cells are also suitable for combination with Raman spectroscopy providing valuable complementary information on the state of the catalyst in working conditions. On-line product analysis is obtained either by mass spectrometry or Raman spectroscopy providing a full description of the activity of the catalyst. These tools are successfully used for time-resolved investigations of heterogeneous catalysts in working conditions using the capability of the Quick-XAS monochromators installed at the SAMBA-SOLEIL beamline. The performances of the full set-up including spectrometers and reaction cells are illustrated by a study of the calcination step of a bimetallic hydrodesulphurisation catalyst and of the activation/reaction processes of a Fischer-Tropsch catalyst. (C) 2012 Elsevier B.V. All rights reserved.