Rapid Analysis of Free Amino Acids in Infant Foods

A new approoch to the analysis of free amino acids from infant foods is described. The method is based on reaction of the free amino acids with phenylisothiocyanate to form stable derivatives which are subsequently separated by liquid chromatography. Sample preparation procedures are described. Separation of all amino acids using this method was completed in 20 min. This method was much faster than the traditional Ion-exchange methods (2–3 h). Variability of the method (expressed as coefficients of variation) for the determination (including preparation of samples, derivatization and liquid chromatography) of all amino acid was less than 10%.