Simultaneous Amino Acid Analysis Based on ¹⁹F NMR Using a Modified OPA-Derivatization Method

To provide alternative methods of analyzing amino acids without liquid chromatography, ¹⁹F NMR-based simultaneous and individual detection methods for amino acids using o-phthalaldehyde (OPA)-based ¹⁹F labeling have been developed. Since the chemical shifts of almost all ¹⁹F-labeled amino acids differ from each other, and they can be discriminated on the ¹⁹F NMR spectrum, simultaneous detection of amino acids has been successfully demonstrated. The discrimination pattern of the peak identical to that of the ¹⁹F-labeled amino acids was largely dependent on the chemical structure of the thiols having ¹⁹F nuclei, strongly suggesting that there is a large potential for clearer discrimination of amino acids by optimizing the thiol structure and/or combined use of thiols.