摘要
气态汞浓度测量技术的提升有助于大气汞的准确监测,可进一步为我国履行《关于汞的水俣公约》提供技术支持,推动汞的污染防治工作。使用微波消解电感耦合等离子体质谱法测量气态汞浓度,研究了样品制备时活性炭粒径和气体流量对活性炭吸附汞效果的影响,样品预处理过程中消解温度、HNO3和HCl的比例以及消解时间对消解效果的影响,并且为电感耦合等离子体质谱测量建立了外标定量方法。结果显示,50目的活性炭及较低的气体流量更利于气态汞的吸附;消解温度为190℃、HNO3与HCl配比为5∶3、消解时间为50 min时消解效果最好。在此方法中,线性相关系数R2为0.999 9,检出限为0.050 9 ng·g-1,线性好、检出限低,可用于气态元素汞的测量。采用外标法依据汞单元素有证标准物质对样品进行了定值,该值与动态发生汞标准的理论值间相对偏差均小于2.5%,证明此方法具有较高的准确性,进一步验证了动态发生法制备汞标准气体的量值准确性。
The improvement of gaseous mercury concentration measurement technology is conducive to the accurate monitoring of atmospheric mercury, which can further provide technical support to the implementation of the“Minamata Convention on Mercury” and promote the prevention and control of mercury pollution in China. In this paper, a microwave digestion and inductively coupled plasma mass spectrometry(ICP-MS) was developed to measure the concentration of gaseous mercury. Specifically, the factors affecting the experimental results were evaluated,including(1) the factors of activated carbon particle size and gas flow to mercury adsorption in sample preparation,and(2) the factors of digestion temperature, volume ratio of HNO3∶HCl and digestion time to the digestion efficiency in sample pretreatment. The external standard method for the quantitative determination of mercury based on ICP-MS was also established. The results showed that 50 mesh activated carbon and lower gas flow were more favorable for the adsorption of gaseous mercury, and the best efficient digestion was obtained when the digestion temperature was 190℃, the volume ratio of HNO3∶HCl was 5∶3, and the digestion time was 50 min. In this method, the linear correlation coefficient R~2 is 0.999 9and the detection limit is 0.050 9 ng·g-1, which shows good linearity and a lower detection limit for the measurement of gaseous elemental mercury. The samples were determined by the external standard method based on the certified reference material of single elemental mercury. The differences between the results calculated by the external standard method and the theoretical data are less than 2.5%, which proves the high accuracy of this method and further verifies the accuracy of the quantity of mercury gas standard prepared by the dynamical generation method.
作者
周枫然
王德发
张体强
叶菁
冯和平
ZHOU Fengran;WANG Defa;ZHANG Tiqiang;YE Jing;FENG Heping(National Institute of Metrology,Beijing 100029,China;National Quality Inspection and Testing Center for Gas Products,Beijing 100029,China)
出处
《计量科学与技术》
2022年第10期65-70,33,共7页
Metrology Science and Technology
基金
中央级公益性科研院所基本科研业务费(AKY1620)。
