High-performance liquid chromatography of amino acids after derivatization with 9-isothiocyanatoacridine

This study describes a reproducible method for the routine determination of amino acids in protein hydrolysates using 9-isothiocyanatoacridine as an HPLC precolumn derivatization reagent. Derivatization is carried out by adding the isothiocyanate dissolved in dry acetonitrile to a buffered amino acid solution without the following extraction of the excess reagent. The resulting N-(9-acridinylthiocarbamoyl)amino acids were separated by one single isocratic HPLC analysis with the UV detection at 280 nm.