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目的建立HPLC同时测定市售绿茶饮料中茶多酚和生物碱含量的方法并考察放置时间对其产生的影响。方法样品经SPE小柱萃取后进样分析。色谱柱为Phenomemex Synergi 4u FusionRP ODS(250 mm×4.6 mm,5μm),流动相为乙腈-水,梯度洗脱,流速为1.0 mL·min~(-1),检测波长为210 nm,柱温为25℃。结果在上述色谱条件下,6个待测成分在测定范围内线性关系良好(r≧0.999 1),平均加样回收率为97.3%~99.1%,RSD≦2.9%(n=9);随放置时间的延长,饮料中茶多酚的含量降低,生物碱含量无明显变化。结论随放置时间的延长,饮料中茶多酚的损失率增加,含量减少,其抗氧化活性有所降低。
Objective To establish a method for the simultaneous determination of tea polyphenols and alkaloids in commercial green tea beverages by HPLC and to investigate the effect of placement time on them. Methods Samples were extracted by SPE cartridge and analyzed by injection. The chromatographic column was Phenomemex Synergi 4u FusionRP ODS (250 mm × 4.6 mm, 5 μm). The mobile phase consisted of acetonitrile-water with a gradient of 1.0 mL · min -1. The detection wavelength was 210 nm and the column temperature was 25 ° C. Results Under the above chromatographic conditions, the six analytes had a good linearity (r ≧ 0.999 1) in the range of determination. The average recoveries were 97.3% ~ 99.1% and RSD ≦ 2.9% (n = 9) With the prolongation of time, the content of tea polyphenols in the beverage decreased and the content of alkaloids did not change significantly. Conclusions With the prolongation of storage time, the loss rate of tea polyphenols in beverage increased, the content decreased, and the antioxidant activity decreased.