ICP-MS法评定奶粉中铝含量的不确定度评定

Uncertainty Evaluation of Aluminium Content in Milk Powder by ICP-MS

分析奶粉中铝的含量的不确定度,从中找出影响不确定度的各种因素。建立相应的数学模型,运用最小二乘法对外标曲线拟合的不确定度进行评定。评定结果显示,当样品中铝含量为0.0738 mg/kg时,其扩展不确定度为0.003 mg/kg(K=2),测定结果表示为(0.0738±0.003)mg/kg。研究建立了测定奶粉中铝含量的不确定度的基本方法,同时对此方法测量的不确定度进行评定,可用于合理的体现测定结果的可靠程度。

To analyze the uncertainty of aluminum content in milk powder and find out any factors that affect uncertainty, a mathematical model was set up, the least-squares method was used to evaluate the uncertainty of the external standard curve. The results showed that when the aluminium in sample contained 0. 0738 mg/kg, extended uncertainty was 0. 003 mg/kg （ K = 2 ）, the determination results expressed as （ 0. 0738 ±0. 003 ） mg/kg. The research established the basic method of determining the uncertainty of the content of the aluminium in milk powder, and evaluated the uncertainty of this method. It can be used to show the reliability of the results.