Methods for the generation and stabilization of alkaline aqueous and/or ethanolic superoxide solutions have been developed utilizing either high energy ionizing radiation or vacuum-uv photolysis. These solutions can be used for the study of the reactivity of superoxide radical (O-2) and its conjugate acid the perhydroxyl radical (HO2) with other compounds over the entire pH range. Frozen, they can be kept at -196 degrees C for prolonged time periods with little loss in superoxide radical. As these solutions can be rendered free of molecular oxygen, studies of the reactivity of HO2/O-2 with oxygen-sensitive compounds under virtually anaerobic conditions are possible.