HPLC electrochemical fluorometric detection of amino acids including tryptophan using 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole.
It has been shown that by electrochemical oxidation 7-nitrobenzo-2-oxa-1,3-diazole-tryptophan (NBD-T) is converted to fluorophores having the same emission and excitation spectra as those for other NBD-amino acids. NBD-dioxindolylalanine was tentatively assumed to be a main electrochemical oxidation product of NBD-tryptophan. A coulochemical cell placed between an analytical column and a fluorometer showed no detrimental effect on the separation of NBD-amino acids by reversed phase HPLC. Highly sensitive fluorescence detection was achieved for amino and imino acids at 10-100 fmol levels. The detection limit for tryptophan was 50 fmol.
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives; D000596:Amino Acids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004563:Electrochemistry; D005456:Fluorescent Dyes; D005470:Fluorometry; D010069:Oxadiazoles / Q000031:analogs & derivatives; D014364:Tryptophan / Q000032:analysis*
D000596:Amino Acids; D005456:Fluorescent Dyes; D010069:Oxadiazoles; C032930:7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole; D014364:Tryptophan; D009327:4-Chloro-7-nitrobenzofurazan