The application of radioisotope labeled molecules gives a sensitive detection method to follow adsorption, desorption and catalytic transformations even in co-reaction with non-labeled compounds. This radiolabeling technique was introduced for study of methanol transformation, first on proton and subsequently on Cs, Cu and Fe ion-exchanged aluminosilicates. This novel method was excellent to follow and analyze methanol transformations on different catalysts. The gas chromatographic (GC) analysis was completed with a radiodetector that could distinguish the radiolabeled derivates from other non-radioactive compounds, reagents or impurities. The radio-GC results confirmed the role of acid, basic and redox sites on H- and metal-modified zeolites and MCM-41 catalysts.