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

[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.