手性衍生-高效液相色谱法拆分和定量测定茶氨酸对映体

建立了以1-氟-2,4-二硝基苯基-5-L-丙氨酰胺（FDAA）为手性衍生试剂、高效液相色谱拆分茶氨酸对映体的方法。采用的色谱条件为：Kromasil C18色谱柱;三乙胺-磷酸缓冲液和乙腈为流动相,梯度洗脱，流速1.0 mL/min;检测波长为340 nm;柱温为35 ℃。L-茶氨酸的进样量在1.732×10-3～2.077 μg范围内峰面积与进样量之间的线性关系良好，加标回收率为97.3%～102.0%,检测限为4.973×10-4 μg,定量限为1.223×10-3 μg。D-茶氨酸的进样量在1.696×10-3～2.044 μg范围内峰面积与进样量之间的线性关系良好,加标回收率为97.2%～103.2%,检测限为5.871×10-4 μg,定量限为1.236×10-3 μg。该方法灵敏度高,分析过程中不发生消旋化。

Separation and Quantification of Theanine Enantiomers Using High Performance Liquid Chromatography Coupled with Chiral Derivatization

L-Theanine is a unique non-protein amino acid in tea, and shows many physiological functions. To directly extract L-theanine from tea is a lengthy and very costly process. Although the chemical synthesis of theanines is simple, the product is unfortunately a mixture of DL-enantiomers. A chiral derivatization method was developed for the separation and quantification of theanine enantiomers by reversed-phase high performance liquid chromatography (RP-HPLC). 1-Fluoro-2,4-dinitrophenyl-5-L-alanine amide (FDAA)was used as the chiral reagent. This method showed good linearity for both L-theanine (ranging from 1.732 x 10(-3) to 2.077 microg) and D-theanine (ranging from 1.696 x 10(-3) to 2.044 microg). The recoveries were in the range of 97.3% - 102.0% for L-theanine and 97.2% - 103.2% for D-theanine. This method also showed excellent limit of detection (approximately 5 x 10(-4) microg) and limit of quantification (approximately 1 x 10(-3) microg) for both L-theanine and D-theanine. The results demonstrated that this method is precise, accurate and can be used for the determination of theanine enantiomers.