High-speed liquid chromatographic analysis of amino acids by post-column sodium hypochlorite-o∼phthalaldehyde reaction

The performance and operating characteristics of a high-speed amino acid analysis system based on post-column reaction with o∼phthalaldehyde and sodium hypochlorite are described. Thirty-minute analysis of all the 16 standard hydrolyzate amino acids is achieved on a 120-mm long column, packed with a 6-μm cation-exchange resin. With minor loss of resolution, a 22-min assay is possible. The column is useable with several commercial buffers, and analyses at the 10-100-pmole levels are demonstrated. Excellent precision (<2% relative standard deviation), linearity (1010 000 pmoles), and column lifetime are reported, together with quantitative correlation data with a ninhydrin system.