An integrated amperometry waveform for the direct, sensitive detection of amino acids and amino sugars following anion-exchange chromatography

This paper describes a new detection method that uses a six-potential waveform to detect all amino acids without derivatization. The detection limits are less than 1 pmol for most of the analytes. The anion-exchange separation uses a ternary gradient with water, 0.25 M sodium hydroxide, and 1.0 M sodium acetate. We present results of waveform optimization experiments designed to minimize gradient artifacts and to achieve optimum conditions for the quantitative analysis of common amino acids. Analytical results for protein hydrolysates are discussed and compared with those obtained by cation exchange followed by ninhydrin derivatization and spectrophotometric detection.