[反相高效液相色谱法直接测定茶叶中的嘌呤碱]

[Direct determination of purine bases in tea by reversed-phase high performance liquid chromatography].

作者信息

Ding M, Yang H, Xiao S, Chen P

机构信息

Department of Chemistry, Tsinghua University, Beijing 100084, China.

出版信息

Se Pu. 1999 Sep;17(5):459-61.

PMID:12552883

Abstract

A reversed-phase high performance liquid chromatographic(RP-HPLC) method for the direct determination of three purine bases(theobromin, theophyllin and caffeine) in tea was developed. An ODS column with Zorbax SB-C18(4.6 mm i.d. x 250 mm, 5 microns) was employed. The aqueous solution of methanol containing 0.05% of acetic acid and 0.25% of N,N-dimethylformamide(DMF) was used as eluent with a flow rate of 0.8 mL/min. In this method, the aqueous extract of tea can be injected into HPLC directly, but in current HPLC methods for purine bases the coexisted tea polyphenols must be pre-separated. The three purine bases in tea were separated without any interference from the coexisted tea polyphenols. This method is simple (without any special sample pretreatment) and sensitive with detection limits (S/N = 3) of 0.7, 0.9 and 1.8 mg/L for theobromin, theophyllin and caffeine respectively. The linear range of the calibration curve of peak area for the three purine bases were from 6 mg/L to 1,000 mg/L with a correlation coefficient (r) of 0.998-0.999.

摘要

建立了一种反相高效液相色谱（RP-HPLC）法直接测定茶叶中的三种嘌呤碱（可可碱、茶碱和咖啡因）。采用Zorbax SB-C18（内径4.6 mm×250 mm，5微米）的ODS柱。以含0.05%乙酸和0.25%N，N-二甲基甲酰胺（DMF）的甲醇水溶液为洗脱剂，流速为0.8 mL/min。该方法中，茶叶的水提取物可直接进样到HPLC中，而在目前测定嘌呤碱的HPLC方法中，共存的茶多酚必须预先分离。茶叶中的三种嘌呤碱得以分离，不受共存茶多酚的任何干扰。该方法简单（无需任何特殊样品预处理）且灵敏，可可碱、茶碱和咖啡因的检测限（S/N = 3）分别为0.7、0.9和1.8 mg/L。三种嘌呤碱峰面积校准曲线的线性范围为6 mg/L至1000 mg/L，相关系数（r）为0.998 - 0.999。