Elucidating the mode of action and thereby opening the way to the design of chemotherapeutic agents is one of the major goals of metal-based anticancer research. Hydrolysis and DNA binding play an important role for pharmaceutical formulation and for exerting anticancer activity. Herein, for the first time the application of capillary zone electrophoresis-inductively-coupled plasma mass spectrometry (CZE-ICP-MS) for studying the hydrolytic stability and the binding of the ruthenium anticancer drug candidates KP418, KP1019, and RAPTA-C to dGMP is described. RAPTA-C was found to hydrolyze fastest and showed the highest reactivity toward the DNA model compound, whereas KP418 was the most stable compound in both these respects.