Determination of proteinaceous free amino acids by gas chromatography

A method was developed for determination of proteinaceous free amino acids by gas chromatography-mass spectrometry (GC-MS). The guanidino group of arginine in amino acid samples was modified with 1,2-cyclohexanedione at room temperature under basic conditions, and all amino acids were directly derivatized with isobutyl chloroformate. The amino acid derivatives formed were analyzed by GC-MS. The method developed was applied successfully for the determination of amino acids in the Japanese alcoholic beverage, sake. [Display omitted] •Arginine was derivatized to a stable volatile compound at room temperatures for gas chromatography.•The two sequential reactions proceeded under aqueous conditions.•Free proteinaceous amino acids in an alcoholic beverage could be determined by gas chromatography-mass spectrometry.