Gas chromatographic analysis of the free amino acid pool of the potato and gas chromatography-mass spectrometry identification of .gamma.-aminobutyric acid and ornithine

The free amino acid pool of the potato has been studied by using the N-heptafluorobutyryl isopropyl ester derivatives. Directly coupled gas chromatography-mass spectrometry allowed positive identification of the amino acids, where earlier work has relied solely on GC retention times. The nonprotein amino acids gamma -aminobutyric acid and ornithine were shown to be present. gamma -Aminobutyric acid was relatively abundant, at 27% of the free amino pool. The analytical procedure described is rapid and simple and, in combination with an established library of mass spectra of amino acid derivatives, provides a routine technique for the identification of free amino acids.