A method for hydrolyzing and determining the amino acid compositions of picomole quantities of proteins in less than...

A method is described for quantitatively hydrolyzing proteins in 45 min and for analyzing the hydrolysates by high-performance liquid chromatography in an additional 52 min. The alpha-amino acids were detected by the fluorescence of their omicron-phthaldialdehyde derivatives. Ten picomoles of each of the commonly occurring alpha-amino acids could be reliably determined. The method described yielded OPA-ethanethiolamino acid derivatives that were stable for 1 1/2 h and the HPLC method produced a better separation than previously published methods.