Determination of total and non-water soluble iodine in atmospheric aerosols by thermal extraction and spectrometric detection (TESI).
Determination of total and non-water soluble iodine in atmospheric aerosols by thermal extraction and spectrometric detection (TESI).
复制标题
通过热萃取和光谱检测 (TESI) 测定大气气溶胶中的总碘和非水溶性碘。
DOI：
10.1007/s00216-010-3923-1
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发表时间：
2010
影响因子：
4.3
通讯作者：
Gilfedder BS
中科院分区：
文献类型：
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作者：
Gilfedder BS
由于碘在对流层臭氧消耗、HO/ ho2比的改变和气溶胶成核中的作用，它最近在大气化学中引起了人们的兴趣。气相碘化学通过非均相反应与气溶胶相紧密耦合，这取决于气溶胶中的碘浓度和形态。迄今为止，气溶胶中总碘测定的唯一方法是在过滤器上通过撞击收集和中子活化分析（NAA）定量。并非所有工作组都能广泛使用NAA，而且委托费用很高。在这里，我们提出了一种方法，通过在1000°C下燃烧过滤器子样品（~ 5 cm2），捕获在去离子水中，并通过UV/Vis光谱进行定量，来确定气溶胶撞击过滤器样品中的总碘浓度。石英和纤维素过滤器从四个单独的采样活动中进行了分析。该方法灵敏（3σ= 6 ng绝对碘≈3 pmol m−3），精确（RSD ~ 5%），通过外部和标准添加校准确定。总的碘浓度从南大洋上空的10 pmol m - 3到热带大西洋上空的100 pmol m - 3不等，与以前的估计一致。然后从总碘中减去可溶性碘浓度（用水提取并用ICP-MS测量），得到非水溶性碘（NSI）。NSI占总碘的比例从20%到53%不等，因此在某些情况下可能很重要。
Iodine has recently been of interest in atmospheric chemistry due to its role in tropospheric ozone depletion, modification of the HO/HO2ratio and aerosol nucleation. Gas-phase iodine chemistry is tightly coupled to the aerosol phase through heterogeneous reactions, which are dependent on iodine concentrations and speciation in the aerosol. To date, the only method available for total iodine determination in aerosols is collection on filters by impaction and quantification by neutron activation analysis (NAA). NAA is not widely available to all working groups and is costly to commission. Here, we present a method to determine total iodine concentrations in aerosol impact filter samples by combustion of filter sub-samples (∼5 cm2) at 1,000 °C, trapping in deionised water and quantification by UV/Vis spectroscopy. Both quartz and cellulose filters were analysed from four separate sampling campaigns. The method proved to be sensitive (3σ= 6 ng absolute iodine ≈ 3 pmol m−3) precise (RSD ∼ 5%) and accurate, as determined by external and standard addition calibrations. Total iodine concentrations ranged from 10 pmol m−3over the Southern Ocean to 100 pmol m−3over the tropical Atlantic, in agreement with previous estimates. The soluble iodine concentration (extracted with water and measured by ICP-MS) was then subtracted from the total iodine to yield non-water-soluble iodine (NSI). The NSI fraction ranged from 20% to 53% of total iodine, and thus can be significant in some cases.