Capillary atmospheric pressure chemical ionization using liquid point electrodes.
Capillary atmospheric pressure chemical ionization using liquid point electrodes.
复制标题
使用液体点电极的毛细管大气压化学电离。
DOI：
10.1002/rcm.6944
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
T. Benter
中科院分区：
文献类型：
--
作者：
Sonja Klee;Marco Thinius;K. Brockmann;T. Benter
基本原理
采用点对面直流放电（“电晕”）操作的大气压化学电离 (APCI) 源经常遭受点电极退化的影响，并可能导致生成的分析物离子氧化和/或碎裂。据推测，这些不利影响是由这些离子与放电化学物质以及在到达质量分析器区域的途中的相互作用引起的。
方法
电晕放电金属点电极被熔融石英毛细管产生的圆锥形液体流出物所取代，这与电喷雾电离中的泰勒锥形成类似但不相同。由纯水或含有 0.1%V 甲酸的水组成的液体通过纳流输送阶段以 1-800 μL/h 之间的典型流速供给。液流不断补充点电极的表面。该源直接连接到适当的质谱仪（例如 Bruker Daltonics 和 Agilent 品种）的入口毛细管。
结果
主动泵送的液流向电晕区域提供 20 ppmV 至 30 %V 范围内的恒定量的反应气 (H2O)，从而实现源的受控且非常稳定的运行。电晕放电观察到的典型光发射非常接近水表面。分析物质子化是主要的电离途径。主要分析物碎裂程度极低。
结论
我们开发了一种新型大气压化学电离源，专为纳流液相色谱和气相色谱与大气压电离质谱联用而设计。所提出的反应机制，包括源中发生的电化学以及通过碰撞诱导解离（CID）形成质子化分析物分子，与实验结果完全一致。该系统在长时间运行下表现出极其稳定的性能，仅产生质子化分子，并且分析物离子碎片程度低。
RATIONALE
Atmospheric pressure chemical ionization (APCI) sources operated with point to plane DC discharges ('Coronas') frequently suffer from point electrode degradation and potentially lead to oxidation and/or fragmentation of the generated analyte ions. It is postulated that these adverse effects are caused by the interaction of these ions with the discharge chemistry as well as en route to the mass analyzer region.
METHODS
The corona discharge metal point electrode is replaced by the conically shaped liquid effluent evolving from a fused-silica capillary, which is analogous but not identical to the Taylor cone formation in electrospray ionization. The liquid consisting of either pure water or water containing 0.1 %V formic acid is fed via a nano-flow delivery stage at typical flow rates between 1-800 μL/h. The liquid flow is continuously replenishing the surface of the point electrode. The source is directly coupled to the inlet capillary of appropriate mass spectrometers, e.g., the Bruker Daltonics and Agilent varieties.
RESULTS
The actively pumped liquid flow is supplying a constant amount of the reagent gas (H2O) to the corona region in the 20 ppmV to 30 %V range, leading to controlled, very stable operation of the source. The typical light emission observed for corona discharges is in very close proximity to the aqueous surface. Analyte protonation is the dominating ionization pathway. The degree of primary analyte fragmentation is extremely low.
CONCLUSIONS
We have developed a novel atmospheric pressure chemical ionization source designed for the hyphenation of nano-flow liquid chromatography and gas chromatography with atmospheric pressure ionization mass spectrometry. The proposed reaction mechanism including the electrochemistry occurring in the source along with formation of protonated analyte molecules via collision-induced dissociation (CID) is in full accord with the experimental results. The system exhibits an extremely stable performance over prolonged operation times, sole generation of protonated molecules, and low degree of analyte ion fragmentation.
DOI：
10.1007/s13361-011-0211-z
发表时间：
2011-11-01
影响因子：
3.2
作者：
Poehler, Thorsten;Kunte, Robert;Benter, Thorsten
通讯作者：
Benter, Thorsten
用于大气相关化合物原位降解产物研究的新型 APPI-MS 设置：毛细管大气压光电离 (cAPPI)
影响因子：
3.2
作者：
H. Kersten;V. Derpmann;I. Barnes;K.J. Brockmann;Th. Benter
通讯作者：
Th. Benter