Reaction of amines of biological importance with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole

Abstract The reaction of amines, amino acids and imino cids with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-F) were investigated by high-performance liquid chromatography (h.p.l.c.) with fluorimetric detection. All the amino compounds tested, except tryptophan, gave fluorescent derivatives at 524–541 nm with excitation at 467–472 nm. The reaction rates for secondary amines, imino acid, primary amine and amino acid decreased in this order. The NBD derivativs of synephrine were separated on h.p.l.c., and fractions were collected and subjected to chemical-ionization mass spectrometry. It is shown that the N -mono-NBD derivative of synephrine, (M + H) + = 331, is formed rapidly and disappears gradually while the N,O -di-NBD derivative, (M + H) + = 494, forms. The h.p.l.c. of putrescine, spermidine and spermine is described; the detection limits are 76 fmol, 0.43 pmol and 1.20 pmol, respectively.