[Determination of theanine in tea leaves by HPLC-inhibited chemiluminescence with Co2+ catalyst].
A method for the separation and determination of theanine in tea leaves has been developed, based on inhibited chemiluminescence of cobalt-catalyzed luminol-H2O2 reaction by theanine. Separations were performed on a YWG-C18 column using a mobile phase of 0.01 mol.L-1 sodium acetate-acetic acid buffer at pH 5.5 at a flow rate of 0.8 mL.min-1. The optimum concentrations of Co2+, luminol, and H2O2 were 2 micrograms.L-1, 0.25 mmol.L-1, and 0.5 mmol.L-1, respectively. Under the conditions mentioned above, the relative peak area (Y) of inhibited chemiluminescence of theanine was linear with the concentration (X) of theanine in the range of 0.2 g.L-1-5.0 g.L-1 and its linear regression equation was Y = 33,862 x + 1.0605 (r = 0.9983). The average recovery was 97.82% with a RSD of 2.16%.
Zhou
Guang-ming
GM
School of Chemistry and Chemical Engineering, Southwest-China Normal University, Chongqing 400715, China. gmzhou@swnu.edu.cn
Yang
Guang-ming
GM
Qi
Dong-mei
DM
Deng
Chuan-yue
CY
Peng
Jing-dong
JD
D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003035:Cobalt; D005971:Glutamates / Q000032:analysis*; D008163:Luminescent Measurements; D008165:Luminol; D018515:Plant Leaves / Q000737:chemistry; D013662:Tea / Q000737:chemistry*
D005971:Glutamates; D013662:Tea; D003035:Cobalt; D008165:Luminol; C026166:theanine