The fluorescence of NBD is highly dependent on the environment; it is virtually nonfluorescent in water but becomes strongly green fluorescent in hydrophobic media. NBD-ethylenediamine can be readily coupled to activated carboxy groups or sulfonyl chlorides.    &lamba;Ex/&lamba;Em (MeOH) = 466/535 nm  Yellow solid soluble in DMSO or DMF  Store at 4°C and protect from light  C8H9N5O3  MW: 223.19