Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This paper describes the determination of acetylsalicylic acid (ASA), paracetamol and caffeine in pharmaceutical formulations using solid-phase molecular fluorescence and second order multivariate calibration. This methodology is applicable even in the presence of unknown interferences and with spectral overlap of the components in the mixture. Parallel factor analysis (PARAFAC) was used for model development, whose effectiveness was demonstrated by analysis of variance (ANOVA). Errors below 10% were obtained for all compounds using an external validation set. Benefits of the new procedures not included in the reference methods such as low cost, no need of sample preparation, simple and fast analysis using fluorescence spectrometer and no generation of waste, make this method very attractive, allowing for the simultaneous determination of compounds with good reproducibility and accuracy. (C) 2008 Elsevier B.V. All rights reserved.64241671212216Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)