ICP-AES法测定原油中镍含量及不确定度评定

采用电感耦合等离子体发射光谱法(ICP-AES)定量分析原油中金属镍元素的含量,建立了测定镍含量不确定度的分析方法。从4个方面评定了不确定度分量的贡献,分别计算其相对标准不确定度,最终得到合成标准不确定度和扩展不确定度。通过分析计算表明,当原油中镍元素含量为19.64mg/kg时,其扩展不确定度为0.20mg/kg(k=2)。其中标准曲线拟合及标准物质自身引入的不确定度为主要影响因素,其次是溶液配制,而试样称量和测量重复性的贡献较小。

Determination of Nickel Content in Crude Oil by ICP-AES and Evaluation of Uncertainty

The content of nickel in crude oil was quantitatively analyzed by inductively coupled plasma emission spectrometry (ICP-AES), and the uncertainty analysis method was established. The contribution of uncertainty component was evaluated from four aspects, and its relative standard uncertainties were calculated respectively. Finally, the synthetic standard uncertainty and expanded uncertainty were obtained. Through analysis and calculation, the expanded uncertainty is 0.20 mg/kg (k=2) when the content of nickel in crude oil is 19.64 mg/kg. The results show that the mainly uncertainty influence factor is introduced by standard curve fitting and standard material itself, followed by solution preparation, while the contribution of sample weighing and measurement repeatability is small.