Analysis of L-Theanine in Tea by HPLC with Post- Column Derivatization
Special Issues
Homogenize 2 g of dry tea leaves with 25 mL of Li220 for 5 min. Centrifuge and filter through 0.45 µm nylon filter.
Theanine is a neurologically active amino acid found in tea plants. L-Theanine is a dominant amino acid in green tea and is responsible for its unique pleasant taste as well as known relaxation effect. Theanine also has been proven to reduce physical and mental stress, and improve cognition and mood.
Table I: Column oven program
Cation-exchange chromatography using post-column Ninhydrin reagent Trione and UV detection has shown unmatched reproducibility and selectivity in the analysis of free amino acids in complex matrices. The Pinnacle PCX post-column derivatization system allows shortening run times by utilizing column temperature gradients.
Table II: HPLC gradient
We introduce a simple and robust method for analysis of L-Theanine in addition to the other free amino acids in tea leaves.
Figure 1: Chromatogram of green tea sample.
Method
Sample Preparation
Homogenize 2 g of dry tea leaves with 25 mL of Li220 for 5 min. Centrifuge and filter through 0.45 µm nylon filter.
Click here to view full-size graphic
Figure 2: Chromatogram of white tea sample.
Pickering Laboratories, Inc.
1280 Space Park Way, Mountain View, CA 94043
tel. (800) 654-3330, (650) 694-6700
Website: www.pickeringlabs.com
