Uncertainty Evaluation of the Content of Cu,Mg,K and Mn in Tea
The contents of Cu,Mg,K and Mn in tea were determined by inductively coupled plasma atomic emission spec-trometry,and the measurement uncertainty was evaluated.The uncertain components was quantified and the combined stan-dard uncertainty and the expanded uncertainty was calculated by the mathematical formula.The results showed that when the confidence level was 95% ,and the coverage factor was 2,the expanded uncertainty was 0.046 mg/kg when the content of Cu was 4.423 mg/kg;the expanded uncertainty was 0.574 mg/kg when the content of Mg was 1 769 mg/kg;the expanded uncer-tainty was 1.186 mg/kg when the content of K was 45 819 mg/kg;the expanded uncertainty was 0.090 mg/kg when the content of Mn was 638 mg/kg.