Solid Oxide Fuel Cells (SOFCs) fed by biogenic fuels are a key renewable energy technology. Fuel contaminants, and sulfur compounds in particular, can strongly decrease SOFC performance. For this reason, their accurate, high sensitivity, and rapid monitoring and the development of successful removal strategies are major challenges in SOFC research. In this work the removal efficiency of commercial activated carbon filters for biogas filtering upstream of an SOFC was investigated using a Proton Transfer Reaction-Mass Spectrometry instrument (PTR-MS). In particular, we tested sulfur compounds by focusing on the effect of co-vapor adsorption (aromatic, carbonyl and chloro-compounds which are biogas pollutants) on filter performance. The results demonstrate the applicability of PTR-MS for investigating covapor effects which are of practical relevance for SOFC development. (C) 2013 Elsevier B.V. All rights reserved.