[Determination of catechins and caffeine in tea and tea beverages by high-performance liquid chromatography].
OBJECTIVE
A high-performance liquid chromatography method was developed for the determination of total tea catechin and caffeine.


METHODS
The catechins needed to be determined are: (-)-catechin, (-)-epigallocatechin, (-)-epigallocatechin gallate, (-)-epicatechin, (-)-epicatechin gallate, (-)-gallocatechin, (-)-gallocatechin gallate, (-)-catechin gallate and caffeine. The catechins in the tea was extracted with water:ethanol (3:7) by sonication for 20 min. After the extraction solution was centrifuged, it was analyzed by HPLC. The column used was a CAPCELL PAK C18 MG (4.6mm I.D. x 150mm) and gradient elution at constant column temperature with 30 degrees C under UV detector with 210nm. Mobile phase A was 0.1% H3PO4 in water, mobile phase B was 0.1% H3PO4 in methanol with the flow rate 1ml/min.


RESULTS
The results showed that the concentration of the catechins and caffeine and their peak areas achieved good linear relation, r > 0.999. The recoveries were between 61.7%-117.3%. RSD was below 10%. With this method, some tea samples were determined, the results were favorable.


CONCLUSIONS
The method can be applied for determination of catechin and caffeine in tea and tea beverages.
Ling
Yun
Y
National Institute for Nutrition and Food Safety, Chinese Center for Diseases Control and Prevention, Beijing 100050, China.
Zhao
Yun-feng
YF
Li
Zhi-jun
ZJ
Zhang
Gong
G
Wu
Yongning
Y
D002110:Caffeine / Q000032:analysis* / Q000302:isolation & purification; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000032:analysis* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D012680:Sensitivity and Specificity; D013662:Tea / Q000737:chemistry*
D013662:Tea; D002110:Caffeine; D002392:Catechin