重量吸附-红外光谱法测定催化剂固体表面酸性的不确定度评定

Evaluation of Uncertainty in Determination of Solid Surface Acidity of Catalyst by Gravimetric Adsorption-Infrared Spectrometry

利用重量吸附-红外光谱法可对固体催化剂表面的吡啶吸附情况以及总酸度进行定量,同时可利用红外特征峰计算出催化剂表面B酸和L酸的含量。对催化剂固体表面酸性定量过程中可能引入的不确定度来源进行了分类和量化,并通过计算各分量的不确定度评估催化剂表面B酸和L酸测定结果的合成标准不确定度,为检测结果可靠性提供依据。结果表明:重量吸附-红外光谱法测定催化剂固体表面酸性的不确定度主要来源为重复测定、重量吸附和样品质量。其中,重复性为最主要的不确定度来源。通过计算得到B酸的相对不确定度为0.0232,L酸的相对不确定度为0.0157。

The adsorption of pyridine on the surface of solid catalyst and the total acidity can be quantified by gravimetric sorption-infrared spectroscopy,and the content of B-acid and L-acid on the surface of solid catalyst can be calculated by infrared characteristic peaks.In this paper,the sources of uncertainty that may be introduced in the quantitative process of solid surface acidity of catalysts were classified and quantified,and the synthetic standard uncertainty of the determination results of B-acid and L-acid on the catalyst surface was evaluated by calculating the uncertainty of each component,which provided the basis for the reliability of the detection results.The results showed that the uncertainty of the determination of solid surface acidity of catalyst by gravimetric adsorption infrared spectrometry was mainly derived from repeated determination,gravimetric adsorption and sample mass.Among them,repeatability was the main source of uncertainty.The relative uncertainty was 0.023 2 for B acid and 0.015 7 for L acid.