AUTOMATED PRECOLUMN DERIVATIZATION OF AMINO-ACIDS WITH ORTHO-PHTHALALDEHYDE USING A HOLLOW-FIBER MEMBRANE REACTOR

An automated precolumn derivatization procedure was developed for the determination of amino acids, involving the reaction of amino acids with o-phthalaldehyde (OPA) and 2-mercaptoethanol using a cation-exchange hollow-fibre membrane reactor, which is immersed in the reagent solution, and a trap column. Column switching is used to transfer OPA-amino acid derivatives from the trap column to an analytical C18 column, and the derivatives are subjected to gradient elution and fluorimetric detection. The detection limit is 0.3-2 pmol for each amino acid. For 20 pmol of amino acids, the precision is 0.9-5.0% (relative standard deviation, n = 5). The determination of amino acids in a protein hydrolysate sample is described. © 1990.