基于水中氰化物测量不确定度评定的检测质量管理

Detection Quality Management Based on Uncertainty Evaluation of Cyanide Determination in Water

通过评定实验室检测的测量不确定度,建立以不确定度指标量化检测质量控制和质量管理效果的方法。以水中氰化物测量不确定度评定为例,采用GUM法和线性拟合法,评定其A类和B类不确定度,着重量化了标准溶液制备、校准曲线回归、检测过程等B类不确度分量,并采用电子表格的统计性能,建立起便于日常检测中快速评定不确定度的方法。实验结果表明,当水样中氰化物的质量浓度为0.125mg/L时,扩展不确定度为0.008mg/L,评定模型中比色管内氰化物的质量引入的不确定度分量最大。评定过程说明了影响实验室检测数据质量的主要因素是人员、仪器、环境、测量方法、取样和以标准物质为代表的试剂;按照RB/T 214-2017的要求对上述因素规范管理,结合本文建立的不确定度动态评定方法,能够保证检测实验室的数据质量。

By evaluating the measurement uncertainty of laboratory testing,a method of quantifying the quality control and quality management effects on testing with the uncertainty index is established.Taking the uncertainty evaluation of cya?nide detection in water as an example,the class A and class B uncertainties are evaluated with the GUM and linear fitting method.The class B uncertainties such as the preparation of standard solution,the regression of calibration curve,and the detection process are quantified.The statistical function of the Excel form is used to establish a method which is convenient for the rapid evaluation of uncertainty in daily detection.The experimental results show that when the mass concentration of cyanide in the water sample is 0.125mg/L,the expanded uncertainty is 0.008mg/L,and the uncertainty component intro?duced by the quality of cyanide in the colorimetric tube in the evaluation model is the largest.The evaluation process shows that the main factors affecting the quality of laboratory test data are personnel,instruments,environment,measurement methods,sampling and reagents represented by reference materials;according to the requirements of RB/T 214-2017,the standard management of the above factors,combined with the dynamic evaluation method of uncertainty established in this paper,can ensure the data quality of the testing laboratory.