Determination of Amino Acids in Corn Seed by Gas Chromatography-Mass Spectrometry

A gas chromatography-mass spectrometry method was developed for the determination of free amino acids from corn inbred lines flour. Amino acids were extracted using 6% trichloroacetic acid. The extracts were purified using an ion-exchange solid phase, derivatized as trifluoroacetic butyl esters, and analyzed. The N-15-methionine was used as the internal standard. The method was repeatable for most of the amino acids (coefficient of variation was in the order of 20%), and good accuracy and limits of detection were obtained. Among the free amino acids determined, the highest concentrations were obtained for aspartic acid, proline, gamma-aminobutyric acid, lysine, alanine, glutamic acid, and histidine. The study established the variation of the free amino acids within the inbred lines.