Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers
Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers
复制标题
DOI：
10.5194/amt-14-4187-2021
复制
发表时间：
2021-06-07
影响因子：
3.8
通讯作者：
Sipila, Mikko
中科院分区：
文献类型：
--
作者：
Wang, Mingyi;He, Xu-Cheng;Sipila, Mikko
在海洋大气中，碘物种对于氧化和新粒子的形成是重要的。了解碘化学和碘新粒子的形成需要高时间分辨率、高灵敏度和同时测量许多碘物种。在这里，我们描述了溴化物化学电离质谱仪(BR-CIMS)在这项任务中的应用。在COSMICS离开室外液滴(云)舱的碘氧化实验中，我们使用了两个BR-CIMS来测量气相碘物种和硫酸，一个耦合到多方案化学电离入口(BR-Mion-CIMS)，另一个耦合到气体和气溶胶入口的过滤器入口(BR-FIGAERO-CIMS)。通过离线校准和与其他仪器的比对，我们定量了BR-MIONCIMS对HoI、I-2和H_2SO_4的灵敏度，得到了5.8×10(6)、3.8×10(5)和2.0×10(5)分子的检出限。Cm(-3)，用于2分钟的积分时间。根据结合能计算，我们估计HIO3的检测下限为1.2×10(5)摩尔。Cm(-3)，基于最大灵敏度的假设。在BR-FIGAERO-CIMS中的检测下限比在BR-Mion-CIMS中高出约一个数量级；例如，对HoI和HIO3的检测下限分别为3.3×10(7)和5.1×10(6)摩尔。Cm(-3)。我们对Mion进气口和FIGAERO进气口的性能进行了比较，结果表明，使用大气压或减压界面的溴化物化学电离质谱仪非常适合测量海洋环境中的碘和硫酸。
Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of a bromide chemical ionization mass spectrometer (Br-CIMS) to this task. During the iodine oxidation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and intercomparisons with other instruments, we have quantified the sensitivities of the Br-MIONCIMS to HOI, I-2, and H2SO4 and obtained detection limits of 5.8 x 10(6), 3.8 x 10(5), and 2.0 x 10(5) molec. cm(-3), respectively, for a 2 min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 x 10(5) molec. cm(-3), based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around 1 order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 x 10(7) and 5.1 x 10(6) molec. cm(-3), respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.