The resolution of five amino acids derivatives by gas chromatography on phenylthiohydantoin derivatives as chiral stastionary phase was investigated. (S)-5-isopropyl, isobutyl, (sec)-butyl and benzoyl derivatives of $N^3-phenyl-2-thiohydantoin$ were synthesized from L-valine, L-leucine, L-isoleucine and L-phenylalanine, respectively. The phases were employed at several column temperatures ($140^{circ}C{sim}210^{circ}C$). The separation factors were compared with each stationary phase with varying R groups. The possible mechanism of chiral recognition was investigated by NMR technique.