气相色谱法测定PVC中增塑剂的不确定度的评估

Uncertainty evaluation of determination of plasticizers in PVC by gas chromatography

气相色谱法测定PVC中增塑剂的测量不确定度的主要来源有:制备样品溶液的不确定度、仪器进样的精密度以及标准物质标称值的不确定度等.文中推导出了各种传播系数的表达式,计算出各不确定度的分量并将其合成.以测定DEHP为例,提供了各参数的采集和计算方法,最后还分析了待测组分峰面积A_x取值不同时不确定度和自由度的变化情况,本文为同类型分析测定的不确定度评估提供了参考模板.

The uncertainty evaluation of determination of plasticizers in PVC by gas chromatography was proposed. Precision of the instrument, uncertainty of the certified values of standard reference materials used in the measurement, and uncertainty arising from the preparation of sample solutions were considered as main sources of the combined uncertainty. Expression of various propagation coefficients, component of uncertainty and the combined uncertainty were deduced and calculated. The determination of DEHP was taken as an example to illustrate the collection of various parameters and the method of calculation. The uncertainty and freedom were basically unchanged in a certain range of A_x value(peak area of the component to be determined). This uncertainty evaluation method can be a template to evaluate that of similar determination by using linear regressive standard curve.