Development and validation of a method for direct, underivatized analysis of free amino acids in rice using liquid chromatography-tandem mass spectrometry.

Inspired by the apparent relationship of free amino acids (FAAs) which are present in minute quantities with the organoleptic characteristics of food, there is an increased demand for analytical methods sensitive in trace level detection. This study presents the validation results of a simple and rapid method developed for direct, underivatized analysis of FAAs in rice using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). The method demonstrated satisfactory selectivity for twenty FAAs with minimum matrix effect.

Validation of a reversed-phase high-performance liquid chromatographic method for the determination of free amino acids in rice using l-theanine as the internal standard.

The study presents the validation results of the method carried out for analysis of free amino acids (FAAs) in rice using l-theanine as the internal standard (IS) with o-phthalaldehyde (OPA) reagent using high-performance liquid chromatography-fluorescence detection. The detection and quantification limits of the method were in the range 2-16μmol/kg and 3-19μmol/kg respectively. The method had a wide working range from 25 to 600μmol/kg for each individual amino acid, and good linearity with regression coefficients greater than 0.