微孔过滤对茶叶儿茶素类和生物碱HPLC检测的影响

本试验分别选用4种不同材质尼龙66（NL66）、聚醚砜（PES）、混合纤维素（MCE）和聚四氟乙烯（PTFE）]滤膜过滤茶样浸提液，考察微孔滤膜过滤对茶叶中没食子酸、儿茶素类和嘌呤碱HPLC分析检测的影响。结果表明同种材质滤膜连续过滤获得3瓶滤液（约1mL/瓶）中的没食子酸和生物碱含量基本相当；尼龙66滤膜过滤液中的儿茶素含量存在较大的瓶间差异，但PES、MCE和PTFE滤膜过滤液并无明显的先后差别。由此可见，PES、MCE和PTFE等是茶样浸提液净化预处理较为适宜的滤膜材质，而吸附作用则可能是引起NL66滤膜过滤液中儿茶素类含量测定结果不一致的主要原因。

Effects of Microfiltration on HPLC Determination of Catechins and Alkaloids in Tea

In this experiment, effects of microfiltration on HPLC determination of catechins and alkaloids in tea were investigated with four different membrane materials, nylon 66 （ NL 66 ） , polyether sulfone （ PES ） , mixed cellulose （ MCE ） and polytetrafluoroethylene（PTFE）. The results indicated that there was no obvious difference in the contents of gallic acid and alkaloids among three auto sampler vials（approximately 1mL per vial） when the tea infusions were continuously filtered with the same membrane. However, the contents of catechins in the filtrates obtained from NL 66 membrane filtration showed more difference between each vial and less difference would be found for MCE, PES and PTFE membrane filtration. These facts suggested that MCE, PES and PTFE filters were more suitable for pretreatment of tea infusions combined with HPLC determination of tea compositions, and the inaccuracy of HPLC determination of tea catechins with Nylon 66 filter might result from its absorption character.