WANG Zeng-ming1,2��GUO Qing-dong2��XIE Fang1,2��WANG Xing-ping1,2��MEI Xing-guo2*
1. School of Chemical Engineering and Pharmacy�� Wuhan Institute of Technology�� Wuhan 430073�� China�� 2. Institute of Pharmacology and Toxicology�� Academy of Military Medical Sciences�� Beijing 100850�� China
Abstract��
OBJECTIVE To establish a HPLC method for the simultaneous determination of two main catechins (EGCG and ECG) and caffeine (CAF) which is a content limited substance in tea polyphenols. METHODS The separation was performed on a C18 column (Agilent ZORBAX SB-C18��4.6 mm��250 mm��5 ��m) with the mobile phase consisting of acetonitrile��A��-0.05% phosphoric acid aqueous solution��B��by gradient elution. The gradient condition was as follows�� 0-18 min��A��12%��18-20 min��A��12%-16%��20-35 min��A��16%. The flow rate was 1 mL��min-1. The column temperature was set at 30 �棬and the UV detection wavelength was 278 nm. RESULTS The linear ranges and correlation coefficients of EGCG��ECG and CAF in tea polyphenols were 159.4-797.0 mg��L-1 (r=0.999 6)��40.16-120.18 mg��L-1 (r=0.999 7) and 1.6-12.8 mg��L-1(r=0.999 9) respectively. The limits of quantitation were 0.8��0.8 and 1.0 ng respectively. The limits of detection were 0.25��0.25 and 0.30 ng respectively. The average recoveries were 98.94%��99.45% and 100.46% with corresponding RSDs of 0.72%��1.00% and 0.83%��respectively. The RSDs were smaller than 2.0%. CONCLUSION The method is simple��accurate��reproducibility and can be used to determine EGCG��ECG and CAF in tea polyphenols.
WANG Zeng-ming,
GUO Qing-dong,
XIE Fang etc
.Determination of Catechins and Caffeine in Tea Polyphenols by HPLC[J] Chinese Pharmaceutical Journal, 2011,V46(21): 1674-1676
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2011, Vol. 46 
