Analysis of amino acid phenylthiohydantoins by high-performance liquid chromatography using gradient elution with ethanol

The use of gradient elution with acetate-buffered ethanol for high-performance liquid chromatographic analysis of phenylthiohydantoins (PTHs) is described. The system separates all commonly encountered PTH derivatives in a total analysis time of 20 min on columns of Spherisorb 5 S ODS (4.6 × 250 mm) packed in the laboratory at moderate expense. Experience with routine operation of the method, particularly with regard to column stability is discussed. Ethanol is considerably cheaper and less toxic than previously described solvent systems.