This study conducted electrospray ionization mass spectrometry (ESI-MS) tests oil 90-95% pure [AlO4Al12(OH)(24)(H2O)(12)]Cl-7 (Al-13) salt dissolved in a 50:50 v/v water/acetonitrile Solution. Acetonitrile typically replaces the ligated aqua ligands and adducts to the aluminum center, leading to aluminium tridecamer breakdown. The chloride anions cannot coordinate with the aluminum center in the presence of acetonitrile molecules. The acetonitrile deconstructs the "cagelike" aluminum tridecamer structure into Smaller polymeric species, which are further transformed into a brucite-like structure. The present work obtained the mass spectra of incremental difference of 18u for fresh Solution and of 9u for aged Solution in the m/z = 200-900 regime, providing Support to the Occurrence of water ligand exchange reaction during aluminum tridecamer decomposition.