Separation And Quantitation Of Theanine Enantiomer By High Performance Liquid Chromatography

L-Theanine is a peculiar non-protein amino acid in tea.It is a new kind of natural product, which is safely and poisonless .L-Theanine has lots of physiological function.The future of its development is extensive. we directly extract L-theanine from tea,which is one of the important ways to use tea's functional ingredient effectively. If we adopt tea as material to produce L-Theanine,the cost of separation and purification is high,it has't the advantage of price,thus influence the scale of industrialization.Chemical synthesis course is simple which can be industrialized, the product is DL-enantiomer,it is difficult to separate and get rid of D-Theanine.People only need L-Theanine which can be absorable and usable.In point of nutrition,It is no perspicuity conclusion for the physiological and active function of D-Theanine .It is necessary to qualitatively and quantitatively study theanine enantiomer. The HPLC method was first established for separation and quantitation of theanine enantiomer and also studied the relationship between temperature and the transform of L-theanine.The main innovate results are as follows:l.Chiral ligand exchange chromatographic stationary phases method was established for the separation of theanin enantiomer.The optimum condition was as follows :L-Hydroxyproline bonded chiral column;mobile phase:0.8mmol/L CuSO₄-H₂O;wavelength:254nm;flow rate :1.0ml/min;column temperature:30℃. There was a good linearity between peak area and injection quantity of L-Theanine range from 0.08126μg⁴.514μg and D-Theanine range from 0.08250μg⁴.583μg.The average recovery rate was 99.12% for L-Theanine and 99.10 % for D-Theanine.The method was simple, stable and accurate.2.Chiral ligand exchange chromatographic mobile phases method was established for the separation of theanin enantiomer.The optimum condition was as follows:Polaris C₁₈ column;mobile phase:L-proline:Cu²⁺=2:1,the concentration of Cu²⁺was 0.5mmol/L,pH6.8,the volume of methanol is 2%; wavelength:254nm;flow rate:0.9ml/min;column temperature:30℃ .There was a good linearity between peak area and injection quantity of L-Theanine range from 0.09542μg⁴.241μg and D-Theanine range from 0.08486μg⁴.243μg.The average recovery rate was 98.76%...