Determination of Dissolving-out Characteristics of Black Tea Elements by Inductively Coupled Plasma Atomic Emission Spectrometry

Black tea is produced by successive procedure such as cranking up of raw material,first rubbing,fermenting,and drying processes,which is rich in a variety of minerals,such as K,Ca,Mg,and Zn. Black tea is benefit for astronauts. In order to investigate the dissolving-out characteristics of black tea,elements of black tea powder and black tea soup were analyzed. The closed high-pressure microwave digestion method was used for sample digestion to avoid the loss of elements during the digestion procedure. The concentration of seven minerals including K,Mg,Al,Mn,Zn,Fe,and Ca were measured by inductively coupled plasma atomic emission spectrometry( ICP-OES). The tea soup was made using deionized water for 5 times. The results showed that the method recoveries ranged from 96. 4% to 106. 7%and the dissolving-out yields of K,Mg,Al,Mn,Zn,Fe,and Ca were 45. 35%,6. 23%,2. 16%,1. 68%,7. 8%,2. 0%,and 0. 4% respectively,in the first tea soup. There was an exponential relationship between the dissolving-out yields of K,Mg,Al,and Mn and soaking times. The exponential relationship equations between the dissolving-out rate for K,Mg,Al,and Mn in black tea and soak times were y = 105. 75e- 0. 874 3x,y = 9. 949 3e- 0. 969 5x,y = 6. 335 8e- 1. 406 5x,and y = 4. 247 7e- 1. 339 4x,respectively. The correlation coefficients were 0. 986,0. 928 3,0. 950 7,and 0. 926,respectively.