Lee Y H, Wängberg I, Munthe J
IVL Swedish Environmental Research Institute, P.O. Box 47086, S-402 58 Goteborg, Sweden.
Sci Total Environ. 2003 Mar 20;304(1-3):107-13. doi: 10.1016/S0048-9697(02)00560-0.
A procedure for sampling gaseous methylmercury (MeHg) in ambient air using a refluxing mist chamber (MC) has been developed. The MC consists of a glass bulb with an air inlet tube at the bottom. Via a capillary mounted adjacent to the inlet tube, the solution inside the MC is pulled from the bottom of the bulb to form a mist inside the chamber. Two different aqueous sampling solutions were tested and evaluated, a dilute HCl (0.003 M) solution and a solution containing the chelating agent ammonium salt of pyrrolidine-1-dithiocarboxylic acid. The airflow rate through the sampler was 10-15 l min(-1). The sampling time was 6 h when using dilute HCl as an extraction solution, and 3 h when using the solution containing the chelating solution. Determination of atmospheric MeHg collected in the aerated water sample was accomplished using GC/CVAFS after aqueous phase ethylation, and pre-collection onto carbotrap column. To test the reproducibility and accuracy of the method, parallel sampling, and standard additions tests were carried out. Other quality control tests, i.e. procedure blanks and duplicated analysis have also been performed. The detection limit, based on three times the standard deviation of total blank (including sampling, distillation, and analysis) is 2 pg, which corresponds to a procedural detection limit of approximately 1 pgm(-3) in ambient air when sampling for 3 h. Measurements performed on the roof of the IVL building yielded concentrations from 3 to 22 pgm(-3) corresponding to 0.3-1% of the total gaseous mercury in ambient air.
已开发出一种使用回流雾室（MC）在环境空气中采集气态甲基汞（MeHg）的程序。该雾室由一个底部带有进气管的玻璃灯泡组成。通过安装在进气管附近的毛细管，雾室内的溶液从灯泡底部被吸出，在室内形成雾状。测试和评估了两种不同的水性采样溶液，即稀盐酸（0.003M）溶液和含有螯合剂吡咯烷 - 1 - 二硫代羧酸铵盐的溶液。通过采样器的气流速率为10 - 15 l min⁻¹。当使用稀盐酸作为萃取溶液时，采样时间为6小时，当使用含有螯合溶液的溶液时，采样时间为3小时。在水相乙基化并预收集到Carbotrap柱上后，使用气相色谱/冷原子荧光光谱法（GC/CVAFS）测定曝气水样中收集的大气MeHg。为了测试该方法的重现性和准确性，进行了平行采样和标准加入测试。还进行了其他质量控制测试，即程序空白和重复分析。基于总空白（包括采样、蒸馏和分析）三倍标准偏差的检测限为2 pg，这对应于在环境空气中采样3小时时约1 pgm⁻³的程序检测限。在IVL大楼屋顶进行的测量得出浓度为3至22 pgm⁻³，相当于环境空气中总气态汞的0.3 - 1%。
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