IMPROVED FLUORIMETRIC DETERMINATION OF HISTAMINE BY STABILIZING O-PHTHALALDEHYDE REAGENT

An improved fluorimetric determination of histamine, based on the formation of a fluorophore between histamine and o-phthalaldehyde (OPT), is obtained if conditions are maintained anhydrous during recrystallization of the OPT and for the preparation and storage of the OPT solution in p-xylene. The increased precision of the method is reflected by a relative standard deviation of 0.007, for 37 aliquots of a p-xylene solution of OPT removed over a 2-week period. The calibration curve is linear above 10 ng of histamine, at which lower limit the fluorescence intensity of the fluorophore is almost twice that of the blank. © 1969.