In this letter, the authors would like to present a rapid method for mass-scale calibration of metastable dissociation in an orthogonalaxis time-of-flight instrument. The calibrating ion is a protonated polyhedral oligomeric silsesquioxane (POSS) generated in electrospray ionization. In addition, dissociation mechanisms for protonated POSS are proposed. Finally, the interest of the method is illustrated in the context of a collision-induced dissociation investigation of sodium-cationized polylactide.