原子吸收光谱法测定青云茶中Mn、Zn、Cu和Fe含量及溶出特性

Determination of Mn,Zn,Cu,Fe Contents and Their Dissolution Characteristics in Qingyun Tea by Atomic Absorption Spectrometry

[目的]探讨不同冲泡方式青云茶水中矿物元素含量的变化规律。[方法]以青云茶叶2 g,用45 ml沸高纯水冲泡5 min 3次,得出3道茶水,用原子吸收光谱法分别测定3道茶水中矿物元素含量;然后改变冲泡时间为10和20 min,测定3道茶水中矿物元素含量;再改变水温为80℃,冲泡20 min,测定3道茶水中矿物元素含量。[结果]云南省金平县青云茶含有丰富的矿物元素Mn、Fe、Zn、Cu,为品质优良茶叶,其茶水中矿物元素含量顺序为Mn〉Zn〉Cu〉Fe。青云茶矿物元素含量以第1道茶水最高,且随冲泡次数的增加而减少。Mn、Zn、Cu元素含量随冲泡时间的增加而增高,Fe元素含量则随浸泡时间增加而减少。80-100℃的水对矿物元素溶出量的影响不大。[结论]用原子吸收光谱法能准确测定茶叶中的矿物元素含量,回收率在97.25%-102.50%,且方法简单、快捷,同一样品处理液可以连续测定多种矿物元素的含量。

[Objective] The study aimed to discuss the change law of mineral elements contents in the tea water of Qingyun tea with different infusing methods.[Method] 3 times of tea water were got by infusing 2 g Qingyun tea with 45 ml boiled high-purity water for 5 min,in which the mineral elements contents were determined by atomic absorption spectrometry.The mineral element contents in the 3 times of tea water were determined again.after the infusing time was changed to be 10 and 20 min and after the infusing time was changed to be 20 min with the water temperature of 80 ℃.[Result] Qingyun tea collected from Jinping County of Yunnan province contained abundant mineral elements of Mn,Fe,Zn and Cu and was the tea with good quality,with the content order of mineral elements in the tea water of Mn 〉 Zn 〉 Cu 〉 Fe.The mineral element contents of Qingyun tea were highest in first time of tea water,and decreased along with the increment of extracting times.Mn,Zn and Cu contents increased,Fe content decreased along with the increment of extracting time.The water with temperature of 80～100 ℃ had little effect on the dissolved amount of mineral elements.[Conclusion] Atomic absorption spectrometry can determine the mineral contents in tea accurately,with the recovery of 97.25%～102.5%.It was simple and fast,and by using this method the contents of multi-mineral elements can be determined continuously with the same sample treating solution.