This test method involves chemically modifying amino acids after hydrolysis to form stable, UV- or fluorescence-detectable derivatives. This enhances detection sensitivity and allows efficient separation using reversed-phase UPLC columns. Samples undergo acid hydrolysis to release free amino acids, which are then reacted with a derivatizing reagent (e.g., AccQ•Tag™) to form stable derivatives. These derivatized amino acids are separated on a reversed-phase UPLC column and detected using UV or fluorescence detectors. Quantification is achieved by comparing to calibration standards.