The tracer oxygen technique has been applied to polycrystalline ceramic and ceramic composites developed for high temperature electrochemical devices with SIMS analysis using a fine focus LMIS primary ion gun. The oxygen tracer distribution in non-uniform and inhomogeneous structures is quantitatively measured by sequential mass spectra and secondary ion imaging on in situ selected and prepared bevel surfaces. (C) 2004 Elsevier B.V. All rights reserved.