Enantiomers were called chiral compounds, which have same chemical formula and structure, but they are each others mirror image.They share the same physical and chemical properties but different in optical property.The increasing need for pure enantiomer is due to that the pharmaceutical activities of the enantiomers in human body are always different and sometimes reverse.L-tryptophan, L-2-amino-3-(indol-3-yl)propionic acid, is a vital constituent of proteins and is indispensable for establishing and maintaining a positive nitrogen balance in human nutrition.As an essential amino acid, L-tryptophan cannot be formed endogenously and is instead considered the precursor of the neurotransmitter serotonin, which plays an important role in brain function and related regulatory mechanisms.Although D-tryptophan shows nospecial biological functions, it has been extensively used as a pharmaceutical intermediate.Due to this difference in nutritional and biological functions of these enatiomers, their chiral separation is a critical, yet challenging task.