The fluorescence of octadecyl rhodamine B in membranes is quenched at high dye concentration but is released at dilution. This property makes the dye useful for membrane fusion assays.    &lamba;Ex/&lamba;Em (MeOH) = 556/578 nm  Dark solid soluble in EtOH or DMSO  Store at -20°C and protect from light  C46H67ClN2O3  MW: 731.50  [65603-19-2]