原子吸收光谱法测定结果不确定度的评定

ASSESSMENT OF UNCERTAINTY OF ANALYTICAL RESULTS OF ATOMIC ABSORPTION SPECTROMETRY

根据ISO导则采用两种量化指标(Ⅰ、Ⅱ)评定原子吸收光谱法的不确定度。量化指标Ⅰ根据实验的操作流程,对不确定度的各来源因素进行量化表述,进而估算总不确定度。不确定度范围较小,可作为实验质量的最高标准,用于评价同一实验人员的测定结果质量。量化指标Ⅱ根据分析过程中的校准、标准物质测定、未知样品测定和分析质量控制四个环节分别对其不确定度各来源因素进行量化表述。采用量化指标Ⅱ评估出的不确定度范围较大,适用于评价不同实验人员或不同实验室之间测定结果的质量。在实际应用中可根据不同的评定对象选择合适的量化指标。

Based on the guidelines given in ISO Guide 1993E, JJF standard and proposals described in literature, the uncertainty of analytical results of AAS was assessed according to two kinds of indexes of quantification, namely index Ⅰ and index Ⅱ. According to index Ⅰ , factors of sources of uncertainty arisen in the process of experimental manipulation were considered and expressed quantificationally, and on the basis of which, the overall uncertainty of the result was evaluated. The range of uncertainty obtained is usually rather narrow, and it is suitable for the judgement of the quality of analysis performed by the same analyst. According to the quantifying index Ⅱ , four key links in the analytical process, i. e. the calibration, the analysis of SRM and of unknoan sample and the control of analytical quality, were considered, and the factors of sources of uncertainty arisen in each of the links were expressed quantificationally. In this case, the range of uncertainty obtained is somewhat wider, and it is suitable to be used in the judgement of the quality of analysis performed by different analysts or laboratories. In practice, the indexes of quantification may be chosen according to the object to be assessed.