Non-fluorescent reagent that reacts readily with primary amines to form highly fluorescent compds: S. Udenfriend et al., Science 178, 871 (1972). Prepn: M. Weigele et al., J. Am. Chem. Soc. 94, 5927 (1972); eidem, J. Org. Chem. 41, 388 (1976). Use as fluorometric reagent: W. Leimgruber, M. Weigele, DE 2350179; eidem, US 3830629 (both 1974 to Hoffmann-La Roche). Review of analytical uses: C. Y. Lai, Methods Enzymol. 47, 236-243 (1977); S. Stein, Peptides in Neurobiology, H. Gainer, Ed. (Plenum, New York, 1977) pp 9-37; S. Udenfriend, Pharmacology 19, 223-227 (1979).