ICP-OES测定茶叶中锰含量的不确定度评价

Evaluation of Uncertainty for Determination of Manganese in tea by ICP-OES

对电感耦合等离子体-原子发射光谱法(ICP-OES)测定3种茶叶中锰含量的不确定度进行评定,通过分析测定过程,确定了测量不确定度主要来源,建立了ICP-OES测定茶叶中锰的不确定度方法。试验表明,锰测量结果的合成标准不确定度分别为0.7 mg/kg,0.7 mg/kg,0.4 mg/kg;当k=2,置信水平为95%时,扩展不确定度分别为1.3mg/kg,1.3 mg/kg,0.8 mg/kg;且标准曲线最小二乘法拟合是该不确定度的主要来源,3种茶叶中锰的质量分数可分别表示为(588.1±1.3)mg/kg,(600.4±1.3)mg/kg,(1278.9±0.8)mg/kg。

The uncertainty in the determination of Manganese（Mn） in 3 kinds of tea by ICP - OES was evalua- ted. The uncertainty factors in the testing process were analyzed and ascertained and the evaluation method of uncer- tainty was established. The results showed that the combined standard uncertainty of Mn measurement results was 0.7 mg/kg, 0.7 mg/kg, 0.4 mg/kg, respectively. Under the conditions of k = 2 and a = 0. 05,the expanded uncertainty of Mn was 1.3 mg/kg, 1.3 mg/kg,0.8 mg/kg the main source of uncertainty. The Manganese （ 1 278.9 ±0.8 ） mg/kg, respectively. , respectively. The standard fitting line with least - square method was in 3 kinds of tea were （588.1 ± 1.3）mg/kg, （600.4 ± 1.3） mg/kg,