Gas chromatographic analysis of histidine: effect on other amino acids present.

Earlier proposals aimed at increasing the detector responses of histidine in gas chromatographic analysis have been compared and contrasted with regard to their effect on the other amino acids present. Twenty-one amino acids have been measured in the form of their N,O,(S)-trifluoroacetyl (TFA) isobutyl esters. Detector responses of the amino acid N,O,(S)-TFA isobutyl esters of dichloromethane solutions alone and mixed with acetic anhydride were recorded and compared with those of other TFA esters. Reproducibility data for chosen representative amino acid N,O,(S)-TFA isobutyl esters are presented.