We have developed a fast and accurate method that uses a small volume of sample to determine over 25 of the typically reported amino acids in human plasma. Samples were prepped with a single step using a spin filter to remove proteins, avoiding the decreased sensitivity from dilution in acid precipitation. Using a reverse phase (RP) High Performance Liquid Chromatography (HPLC) system with O-phthaldehyde (OPA) as the pre-column derivatization reagent, and UV detection at 338 nm, we did a direct comparison with the most common ion exchange/ninhydrin method used in clinical labs on the same plasma samples with 95% concurrence, analysis of amino acid standard solutions returned 99% concurrence. With a sample preparation time of 30 min, utilizing less than 25 μl of sample and with a chromatography run of 30 min, this method can substantially increase access to analysis in both clinical and research laboratories using instruments that are more widely available.
Synopsis: We describe a rapid and easily deployed method for sensitive amino measurement in biological samples.
Keywords: Amino acid; Clinical biochemistry; HPLC; IEM; Inborn error of metabolism.
© 2022 The Authors.