Cereal Chem 62:97-102   |  VIEW ARTICLE
High Performance Liquid Chromatography Analysis of Amino Acids at the Picomole Level.

G. L. Lookhart and B. L. Jones. Copyright 1985 by the American Association of Cereal Chemists, Inc. 

A method was developed for analyzing the amino acid compositions of protein hydrolysates by high performance liquid chromatography (HPLC) in less than 1 hr. Ten picomoles of each of the commonly occurring alpha-amino acids could be reliably determined by the fluorescence of their omicron- phthaldialdehyde (OPA) derivatives. The OPA-derivatization method, which uses ethanethiol as the sulfhydryl reagent, yields amino acid derivatives that are more highly fluorescent than OPA/mercaptoethanol derivatives and are stable for at least 2 1/2 hr. This HPLC method gives a better separation than previously published methods. Amino acid analysis down to the 3-pmol level is demonstrated, and problems associated with analyses at the low picomole level are discussed.