FLUORIMETRIC DETERMINATION OF MONOSUBSTITUTED GUANIDINO COMPOUNDS WITH BENZOIN-DIMETHYLFORMAMIDE REAGENT

A sensitive fluorimetric method for the determination of monosubstituted guanidino compounds is based on their reaction in potassium hydroxide solution with benzoin in the presence of dimethylformamide. The fluorescence produced is stabilized by β-mercaptoethanol and shows excitation and emission maxima around 325 and 435 nm, respectively. The method is simple, selective for monosubstituted guanidino compounds, including polypeptides with one or two arginyl residues, and sensitive; compounds can be determined at concentrations as low as 0.08-0.22 nmol ml-1. © 1979.