Fundamental understanding of aerosol formation during laser ablation is important for the development of LA-ICP analysis of complex samples. Using a Lina Spark Atomizer (TM), the application of this technique to the field of heterogeneous catalysis gave an accuracy of 5-15% while extreme values of + 100% could be obtained in some cases. To improve understanding of laser ablation processes, particles generated during ablation of alumina based catalysts were collected and analysed using different microscopy and surface analysis techniques. Morphological study by scanning electron microscopy showed that most of the particles leaving the ablation cell were nanoparticle aggregates generated from vapor condensation. An XRD study of these aerosols revealed that the condensation converge on the formation of a spinel structure with large coherence domains. Elemental composition of the aerosol was also followed and exhibited differences between a catalyst containing large Mo concentration or low Pt concentration. (C) 2009 Elsevier B.V. All rights reserved.