A Novel Determination Method of Thirty-Seven<i> o</i>-Phthalaldehyde-Derivatized D/L-Amino Acids with Complementary Use of Two Chiral Thiols by High Performance Liquid Chromatography

Simultaneous separation of 37 proteinogenic D/L-amino acids excluding proline with HPLC is generally difficult. In this study, two sets o-phthalaldehyde (OPA)-based fluorescent diastereomers were formed using chiral thiols N-acetyl-L-cysteine (NAC) and N-isobutyryl-L-cysteine (NIBC) independently. It expected that obtained OPA-derivatized D/L show different retention selectivity in reversed phase chromatography because NAC NIBC have hydrophobicities. The independent methods designed to obtain complementary separations for the acids. chromatograms provided complete determination After optimization conditions, types automated analytical procedures investigated. One was OPA/NAC OPA/NIBC derivatization amino originally equipped pretreatment functions auto-sampler. other switching during consecutive batch run. Through these re-consideration procedures, finally method afforded satisfactory peak area repeatability 1.5%RSD or less calibration curve linearity 0.999 greater each diastereomers. established applied real liquor samples successful results obtained.