Role of Gas-Phase Halogen Bonding in Ambient Chemical Ionization Mass Spectrometry Utilizing Iodine
Role of Gas-Phase Halogen Bonding in Ambient Chemical Ionization Mass Spectrometry Utilizing Iodine
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DOI：
10.1021/acsearthspacechem.9b00030
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发表时间：
2019-07-01
影响因子：
3.4
通讯作者：
Finlayson-Pitts, Barbara J.
中科院分区：
文献类型：
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作者：
Ganske, Jane A.;Wingen, Lisa M.;Finlayson-Pitts, Barbara J.
环境电离过程越来越广泛地用于测量与大气有关的粒子和气体。我们在这里报告环境电离质谱利用碘的商业酊剂和压电放电枪（PDG）来产生电离试剂。分析物包括Cl-2、Br-2、HNO3、C-1-C-9系列饱和单羧酸、苯甲酸、2,2-二甲基丙烷酸、9-癸酸和三氯乙酸。当Cl-2和Br-2形成[M + I]（-）碘化物加成物时，HNO3和有机酸出现了意想不到的峰，对应于[2M - 2H + I]（-）。对于HNO3，形成的新离子被解释为[NO3-中心点中心点中心点IONO2]络合物，其中IONO2可能是由HOI与气态NO3-反应形成的。同样，对于有机酸，[2M - 2H + I]（-）峰被解释为[RC(O)O-中心点中心点中心点IOC(O)R]配合物，是由RC(O)O-与酰基次碘酸盐[RC(O)OI]结合形成的。提出(1)Cl-2和Br-2与I-缔合，(2)IONO2与NO3-离子缔合，(3)RC(O)OI与羧酸盐离子缔合是通过非共价卤素键发生的。结果表明，卤素键可能在大气中的化学转化中发挥作用，特别是在碘化物质浓度可能很高的粒子中。
Ambient ionization processes are becoming more widely used for the measurement of atmospherically relevant particles and gases. We report here ambient ionization mass spectra utilizing a commercial tincture of iodine and a piezoelectric discharge gun (PDG) to generate the ionizing reagents. Analytes include Cl-2, Br-2, HNO3, the C-1-C-9 series of saturated monocarboxylic acids, benzoic acid, 2,2-dimethyl-propanoic acid, 9-decenoic acid, and trichloroacetic acid. While Cl-2 and Br-2 form the [M + I](-) odide adducts, HNO3 and the organic acids show unexpected peaks corresponding to [2M - 2H + I](-). For HNO3, the new ion formed is interpreted as the [NO3-center dot center dot center dot IONO2] complex, where IONO2 is likely formed upon reaction of HOI with gaseous NO3-. Similarly, for the organic acids, the [2M - 2H + I](-) peaks are interpreted as [RC(O)O-center dot center dot center dot IOC(O)R] complexes formed by association of RC(O)O- with acyl hypoiodites [RC(O)OI]. It is proposed that the association of (1) Cl-2 and Br-2 with I-, (2) IONO2 with NO3- ions, and (3) RC(O)OI with carboxylate ions occurs via non-covalent halogen bonding. The results suggest the possibility that halogen bonding may play a role in chemical transformations in the atmosphere, particularly in particles where concentrations of iodinated species may be significant.