Synthesis of Levofloxacin based Chiral Reagent and its Application in Determination of Optical Purity of Essential Racemic Amino Acids using RP-HPLC

In this report, the activated chiral reagents of the (S)- levofloxacin (CR-Lfx) were prepared via coupling reaction of N-hydroxysuccinimide and characterised by UV, IR, HRMS, NMR and CHNS. Three essential racemic amino acids were chosen for the chiral recognition study. The diastereomeric derivatives of the chosen amino acids were prepared under microwave heating conditions, using highly reactive activated reagents (CR-Lfx). RP-HPLC was used to separate the prepared diastereomeric derivatives. The effect of varying mobile phase concentrations and sample concentrations was optimised. The density functional theory calculations were performed using Gaussian 09 rev A.02 and hybrid density functional B3LYP with 6-31G* basis set software to create the lowest energy optimised structures of diastereomeric derivatives. LOD (0.208 ng mL−1), LOQ (0.624 ng mL−1), calibration range (0.02-2.0 mg mL−1), correlation coefficient (0.998) and recovery were the validation parameters for our method (99.54 and 99.89 percent for intra-day assay and 99.87 and 99.32 percent for inter-day assay).