State Key Laboratory of Urban Water Resource and Environment , Harbin Institute of Technology , Harbin , Heilongjiang 150040 , P.R. China.
Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
Anal Chem. 2018 Jun 19;90(12):7154-7157. doi: 10.1021/acs.analchem.8b02498. Epub 2018 Jun 7.
A simple and effective approach to studying the mechanism of electrooxidation of aniline (ANI) is reported in this paper. It was accomplished by an innovative electrochemistry (EC)-mass spectrometry (MS) coupling, which can sample directly from a droplet-scale reacting electrolyte for mass spectrometric analysis. With this setup, the polymer chain growth of ANI could be monitored in situ and in real-time. The short-lived radical cations (ANI, m/ z 93.06) as well as the soluble dimer ( m/ z 183.09) and oligomers ( m/ z 274.13, 365.18, ...) were successfully captured. Using the EC-MS and tandem mass spectrometry, the dimers produced by head-to-tail (4-aminodiphenylamine), head-to-head (hydrazobenzene), and tail-to-tail (benzidine) coupling of radical cations were found in the same polymerization process. Moreover, the EC-MS method was also applicable for determining the propagation speed of ANI when applying different electrolyte salts and oxidizing potentials.
本文报道了一种简单有效的研究苯胺（ANI）电氧化机理的方法。通过创新的电化学（EC）-质谱（MS）耦合实现，该方法可以直接从液滴尺度的反应电解质中取样进行质谱分析。通过该装置，可以原位实时监测 ANI 的聚合链生长。成功捕获了短寿命的自由基阳离子（ANI，m/z93.06）以及可溶性二聚体（m/z183.09）和低聚物（m/z274.13、365.18、...）。使用 EC-MS 和串联质谱，在相同的聚合过程中发现了由自由基阳离子的头到尾（4-氨基二苯胺）、头到头（联苯肼）和尾到尾（联苯）偶联生成的二聚体。此外，该 EC-MS 方法还适用于在应用不同电解质盐和氧化电势时确定 ANI 的增长速度。
