Use of a ternary gradient for the separation of phenylthiohydantoin-amino acids, including the methyl esters of aspartic and glutamic acids, by high-performance liquid chromatography

The phenylthiohydantoin (PTH) derivatives of the common amino acids can be resolved in a single high-performance liquid chromatographic analysis by elution from a cyanopropylsilane column with a ternary gradient of methanol, acetonitrile, and ammonium acetate. The system is compatible with an automated sequencer-automated converter combination that produces the methyl esters of PTH-aspartic and PTH-glutamic acids.