The development of an analytical method for the determination of platinum in MgO based Pt/Sn catalysts is described. Electrothermal atomic absorption spectroscopy (ETAAS) was chosen because of its high sensitivity and robustness against spectral interferences. All the sources of chemical interferences were statistically analyzed and corrections were adopted for the presence of magnesium oxide support. The effectiveness of different mineralization procedures was critically evaluated as a function of the chemical of the solid catalyst. Microwave digestion allowed recovery of metal of 100% for all the catalysts analyzed and exhibited significant better precision values than other digestion methods, which could nevertheless be utilized under proper conditions in selected cases.