ABSTRACT
The traditional approach to amino acid analysis, based on ion-exchange separation followed by post-column derivatization with ninhydrin or orthophthalaldehyde (OPA), is not as sensitive as the reversed-phase chromatography technique, but has proven reproducibility and reliability. The dedicated analyzer AlphaPlus developed by Pharmacia LKB and utilizing the post-column derivatization technique, is a well-established instrument and is widely used in routine analysis for example in clinical laboratories and for the quality control of feedstuffs. The AminoSys system from Pharmacia LKB is a modular high-performance liquid chromatography system for amino acid analysis with automated pre-column derivatization and computer control and evaluation. Derivatization of amino acids with phenylisothiocyanate (PITC), also known as Edman's reagent, is widely used by protein chemists. PITC has the advantage of being a well-known reagent which also reacts with secondary amines. The demand has arisen for an alternative reagent to OPA and PITC for pre-column derivatization and which combines the advantages of both.
