凤凰茶汤F~-·Cl~-·NO_2~-·NO_3~-的同时测定

目的]同时测定凤凰茶汤中F-、Cl-、NO2-、NO3-的含量。方法]利用WIC!Ⅱ型离子色谱仪,测定凤凰白叶单丛(分春茶、暑茶、秋茶)及凤凰玉兰香(雪片)4种不同季节收获的凤凰茶汤中F-、Cl-、NO2-、NO3-的含量。结果]各离子的色谱图、检出限和线性方程表明离子色谱法可以同时测定茶汤中F-、Cl-、NO2-、NO3-的含量。凤凰茶汤中F-含量较高,不同季节茶的F-含量是春茶<雪片<暑茶<秋茶,且浸泡时间越长,F-含量越高。茶汤中Cl-含量是适宜的。不同季节茶的NO2-含量是春茶<雪片<秋茶<暑茶,NO3-含量是暑茶、秋茶含量较低,春茶、雪片含量偏高。浸泡时间越长,茶汤中NO2-、NO3-的含量越高。结论]不同季节的凤凰茶中各种阴离子的含量不同造成茶品质不同。

Simultaneous Determination of F-,Cl-,NO2- and NO3- in Fenghuang Tea Soups

Objective] The study aimed to determine the contents of F-,Cl-,NO2-and NO3-in Fenghuang tea soups simultaneously.Method] WIC-Ⅱ ion chromatograph was used to determine the contents of F-,Cl-,NO2-and NO3-in the tea soups of 4 Fenghuang teas of Baiyedancong(spring,late summer and autumn teas) and Yulanxiang(Xuepian),which were harvested in different seasons.Result] The chromatograms,detection limits and linear equations of various ions showed that ion chromatography could determine the contents of F-,Cl-,NO2-and NO3-in the tea soups simultaneously.The F-content was higher in Fenghuang tea soups.The F-contents in teas harvested in different seasons were spring tea < Xuepian < late summer tea < autumn tea and the longer the soaking time was,the higher the F-content was.The Cl-contents in the tea soups were suitable.The NO2-contents in teas harvested in different seasons were spring tea < Xuepian < autumn tea < late summer tea.The NO3-contents were lower in late summer and autumn teas and a little higher in spring tea and Xuepian.The longer the soaking time was,the higher the contents of NO2-and NO3-in the tea soups were.Conclusion] The content differences of various anions in Fenghuang teas harvested in different seasons caused the difference of tea quality.