MitoROS™ 580 can diffuse across the cytoplasmic and mitochondrial membranes, therefore directly measuring superoxide within the mitochondria.  Dihydroethidium, on the other hand, is retained in the cytosol. MitoROS™ shares similar characteristics with Invitrogen’s MitoSOX™ Red. Therefore, experiments utilizing MitoSOX™ Red can be replaced with MitoROS™ 580 without any sacrifice in assay sensitivity. In fact, MitoROS™ 580 is less likely to be oxidized by other reactive oxygen species and reactive nitrogen species.