Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, vvi, Brno, Czech Republic.
Anal Chim Acta. 2012 Feb 10;714:68-75. doi: 10.1016/j.aca.2011.11.054. Epub 2011 Dec 3.
A specially designed annular diffusion denuder for simultaneous removal of organic gaseous compounds and atmospheric oxidants in carbonaceous aerosol sampling is presented. Various kinds of denuder coatings were compared with respect to the collection efficiency of both organic gaseous compounds and NO(2) and ozone. The optimum sorbent is a mixture of activated charcoal and sulfite on molecular sieve. To ensure high collection efficiency over long-term field operation, two annular diffusion denuders are combined in series. The first half of the first denuder is filled with Na(2)SO(3) on molecular sieve (23 cm long layer) while the second half of the first denuder and the whole second denuder are filled with activated charcoal (the total length of the charcoal section is 67 cm). At a flow rate of 16.6 L min(-1), the collection efficiency of organic gaseous compounds and atmospheric oxidants in the annular diffusion denuder is better than 95%. Only small losses of aerosol particles (<3.6% in number concentration) were observed in the size range 0.12-2.26 μm. The annular diffusion denuder is compatible with the collection of aerosols on 47-mm diameter quartz fiber filters at a flow rate of 16.6 L min(-1). The use of this denuder enables one to sample carbonaceous aerosols on filters without positive sampling artefacts from volatile organic compounds and interferences from atmospheric oxidants. The annular diffusion denuder has been applied successfully for the sampling of carbonaceous aerosols during field campaigns of typically 1 month each at urban and forested sites in Europe.
介绍了一种专门设计的用于同时去除碳质气溶胶采样中有机气态化合物和大气氧化剂的环形扩散吸收管。比较了各种吸收管涂层，以评估它们对有机气态化合物和 NO2以及臭氧的收集效率。最佳的吸附剂是活性炭和亚硫酸氢盐分子筛的混合物。为了确保在长期野外作业中具有高收集效率，两个环形扩散吸收管串联使用。第一个吸收管的前半部分填充 Na2SO3分子筛（23cm 长的层），而第一个吸收管的后半部分和整个第二个吸收管填充活性炭（活性炭部分的总长度为 67cm）。在 16.6Lmin-1的流速下，环形扩散吸收管对有机气态化合物和大气氧化剂的收集效率优于 95%。在 0.12-2.26μm 的粒径范围内，气溶胶颗粒的损失很小（数量浓度小于 3.6%）。环形扩散吸收管与在 16.6Lmin-1流速下收集 47mm 直径石英纤维滤纸上的气溶胶兼容。使用这种吸收管可以在不产生挥发性有机化合物的正采样干扰物和大气氧化剂干扰的情况下，在滤纸上收集碳质气溶胶。该环形扩散吸收管已成功应用于欧洲城市和森林地区的野外考察中，每个考察通常持续 1 个月，用于采集碳质气溶胶。
