Dihydrorhodamine 123 itself is non-fluorescent, but it readily enters cells and is oxidized by oxidative species or by cellular redox systems to the fluorescent rhodamine 123 that accumulates in mitochondrial membranes. Dihydrorhodamine 123 is useful for detecting reactive oxygen species including superoxide (in the presence of peroxidase or cytochrome c) and peroxynitrite. Dihydrorhodamine 123 dihydrochloride is functionally equivalent to dihydrorhodamine 123 but with increased stability toward air oxidation and light during storage. White solid soluble in DMF Store at -20°C and protect from light, especially in solution C20H20Cl2N2O3 MW: 419