An overview of the application of FTIR to the quantification of adsorption sites on solid acids, metal particles and to hydrocarbon chains formed during Fischer Tropsch synthesis is reported. The procedures employed in obtaining molar absorption coefficients for transmittance FTIR are described along with a review of pertinent data reported for the three topic areas covered. The limitations and challenges in each case are outlined. (C) 2015 Elsevier B.V. All rights reserved.