Temperature-programmed desorption (TPD) and a differential form of it, called intermittent temperature-programmed desorption (ITPD), turned out to be powerful characterising techniques for chemoresistive materials applied togas sensing. We investigated samples of SnO2, TiO2 and solid solutions of them (TixSn1-xO2). TPD and ITPD experiments were carried out in vacuum, with samples previously treated in pure O-2 (100 Torr, 500 degrees C, 30 min). Amounts of desorbed O-2 corresponded for all Ti-containing samples to less than 10% of a compact monolayer of ions O2-. Corresponding values of the apparent activation energy of desorption (E-app) were calculated directly from the Arrhenius plots for each partial TPD and ranged from about 100 to 330 kJ mol(-1) (1.16 to 3.82 eV). (C) 2009 Elsevier B.V. All rights reserved.