RP-HPLC和MALDI-TOF质谱技术研究茶多酚锰的组成、结构及稳定性

Composition,Structure and Stability of Tea Polyphenol-manganese Revealed by RP-HPLC and MALDI-TOF Mass Spectrometry

选用C18色谱柱对茶多酚锰的组分进行RP-HPLC分离,并用MALDI-TOF质谱技术鉴定其组成与分子结构.用弱酸性介质(pH3.0)作为分离条件,可明显改善茶多酚锰色谱分离的分离度,但却使表没食子儿茶素没食子酸酯-Mn(EGCG-Mn)分解成表没食子儿茶素-Mn(EGC-Mn)和没食子酸(棓酸)-Mn(GA-Mn),说明EGCG-Mn化合物对弱酸体系呈现出不稳定特性.当分离介质的酸度降低到pH4.0时,EGCG-Mn金属有机化合物表现出分子结构的稳定性.实验结果表明:在恰当的酸性介质条件下,建立的茶多酚锰分离技术,可获得质谱纯多酚化合物.

RP-HPLC equipped with C18 chromatographic column was used to separate the complex composition of tea polyphenol-manganese（TP-Mn）.Then MALDI-TOF mass spectrometry（MALDI-TOF MS） was used to identify further the molecular structures and compositions of these polyphenol compounds.It was found that under the condition of weak acid medium（pH3.0）,the chromatographic method can improve the separating size of TP-Mn evidently,but this（-）-epiallocatechin gallate-Mn（EGCG-Mn） was easily decomposed into（-）-epigallocatechin-Mn（EGC-Mn） and gallic acid-Mn（GA-Mn） synchronously,showing that EGCG-Mn compound exhibited unstable characteristics in the medium of weak acid.The metal organic compound EGCG-Mn showed the stability of molecular structure once the acidity of separation medium decreased to pH4.0.The experimental results showed that polyhydric phenol compounds with purify of mass spectrometry can be obtained by these separation techniques described here under the condition of optimal acidic medium.