气态元素汞校准的一致性光学评定检测实验研究

Experimental Study on Consistency Optical Evaluation and Detection of Gaseous Element Mercury Calibration

利用低压汞灯作为光源,结合单色仪,对汞渗透管法和汞饱和蒸气法气态元素汞校准进行一致性光学评定检测研究。在汞渗透管实验中,吸收度面积值与理论浓度的皮尔逊相关系数为0.9968,拟合优度为0.9936,说明两组数据相关性较好且符合郎伯比尔定律。取实验的吸收截面作为标准参考吸收截面,对相同浓度汞蒸气横向对比及不同浓度汞蒸气纵向对比,浓度误差最大为7.45%,表明渗透管法的稳定性较好且精度较高,验证了渗透管法作为汞标气法的可行性。在渗透管实验中加入SO_(2),气态汞浓度测量误差最大为12.82%,说明SO_(2)对汞吸收度测量产生一定程度的干扰。汞饱和蒸气法实验中,以渗透管为基准测得的最大误差在标准允许误差之内,表明2种校准方法具有一致性。但汞饱和蒸气法与渗透管法相比,其重复性及精度仍有不足,待提升空间较大。

Using low-pressure mercury lamp as light source,combined with the monochromator,the consistency of mercury calibration by mercury permeation tube method and mercury saturated vapor method was studied.In the mercury permeation tube experiment,the Pearson correlation coefficient between the absorption area value and the theoretical concentration was 0.9968,and the goodness of fit was 0.9936,indicating that the two groups of data were well correlated and in accordance with Lamberbeer s law.Taking the absorption cross section of the experiment as the standard reference absorption cross section,it was found that the maximum concentration error was 7.45%for horizontal comparison of mercury vapor with the same concentration and vertical comparison of mercury vapor with different concentration.The above results showed that the permeation tube method is feasible,stable and accurate.When SO_(2)was added to the permeation tube experiment,the maximum measurement error of gaseous mercury concentration was 12.82%,indicating that SO_(2)interfered with the measurement of mercury absorption degree to a certain extent.In the experiment of mercury saturated vapor method,the maximum error measured with the permeation tube as the reference was within the allowable error of the standard,indicating that the two calibration methods were consistent.However,compared with the permeation tube method,the repeatability and accuracy of the mercury saturated vapor method were still insufficient,and there was a large room for improvement.