分析方法标准验证实验中不同方法结果间一致性判据研究

不同分析方法间测定结果的比较,用于判断两方法间一致性,是检测实验室经常遇到的实际问题。其应用背景包括方法标准验证实验中,新方法与经典方法间的比较。特别是在缺少标准样品,不满足t值检验的数据条件下,选用合适判据尤其重要。利用波长色散X射线荧光光谱(WD-XRF)和能量色散X射线荧光光谱(ED-XRF)测定土壤、水系沉积物中As、Pb、Cu、Zn、Ni、Cr、Co、V、Mn等重金属一组数据,探讨了比值法、线性模型回归参数法、基于相对偏差的t值检验法、基于与相对偏差限值比较的合格率等判据用于判断结果一致性的可能性。研究结果表明,对一组验证样品,分别用两种分析方法测定,取各元素两组测定结果相对偏差,与相关限值比较,根据合格率大小可以判断两方法结果一致性。方法符合日常质控技术规范,实用性强。基于经验模型公式得到的相对偏差限值填补了质控规范中部分元素空白,奠定了此判据的应用基础。其他判断方法,如比值法(图示法),回归模型法(斜率、相关系数)以及基于相对偏差的t值检验法均有助于发现问题,可协助判断方法间的一致性。

Study on consistency criterion between the results of different analytical methods in standard verification experiments

The comparison of measurement results between different analytical methods is used to judge the consistency between the two methods, and it is a practical problem often encountered by testing laboratories. Its application background includes the comparison between the new method and the classic method in the method standard verification experiment. Especially in the absence of standard samples and data conditions that apply the t-value test, it is particularly important to choose the appropriate criterion. The contents of heavy metals such as As, Pb, Cu, Zn, Ni, Cr, Co, V and Mn in soil and water sediments were determined by wavelength dispersion X-ray fluorescence spectrometry (WD-XRF) and energy dispersion X-ray fluorescence spectrometry (ED-XRF). A group of data were used to discuss explore the possibility for judgment of significant differences in results using the ratio method, linear model regression parameters, t-value test method based on relative deviation, and pass rate based on comparison with relative deviation limit. The results showed that: a group of verification samples were measured by two methods; when the relative deviations of two measurement results of elements were compared with the relevant limits, the pass rate could be used to determine consistency of the results of the two methods. The proposed method complied with the daily quality control technical specifications and had strong practicability. The relative deviation limits obtained from empirical model formula filled up the blanks of some elements in the quality control specifications, which laid the foundation for the application of this criterion. Other judgment methods, such as the ratio method (graphic method), the regression model method (regression slope, correlation coefficient), and the t-value test method based on relative deviation were helpful for finding problems and could help to determine the consistency between the methods.