A new set-up for conducting differential electrochemical mass spectroscopy (DEMS) analysis at temperatures between 120 and 180 degrees C is presented. It enables the characterization and testing of model electrodes in a three electrode assembly under experimental conditions close to those in a high temperature proton exchange membrane fuel cell (HT-PEMFC). This is of special interest for the study of the degradation of fuel cell materials as well as the electro-oxidation reactions of small organic molecules used in direct alcohol fuel cells (DAFCs). While other DEMS set-ups only allow for studying reactions occurring in a liquid electrolyte, the HT-DEMS set-up makes it possible to study reactions in the gas phase. The design of the set-up is presented. Cyclic voltammetry (CV) measurements at 150 degrees C were carried out on Pt/C and Pt black catalysts under nitrogen atmosphere. Oxidation of adsorbed CO and bulk oxidation of ethanol were performed on Pt/C. (C) 2015 Elsevier B.V. All rights reserved.