Time-resolved mass-spectral characterization of ion formation from a low-frequency, low-temperature plasma probe ambient ionization source
Time-resolved mass-spectral characterization of ion formation from a low-frequency, low-temperature plasma probe ambient ionization source
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DOI：
10.1039/c3ja50318f
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发表时间：
2014-01
影响因子：
3.4
通讯作者：
J. Shelley;Arne Stindt;Jens Riedel;C. Engelhard
中科院分区：
文献类型：
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作者：
J. Shelley;Arne Stindt;Jens Riedel;C. Engelhard
受环境解吸/电离质谱的出现的启发，对质谱电离源的开发产生了新的兴趣，导致了等离子体源开发和表征的复苏。介质阻挡放电，特别是低温等离子体（LTP）探针格式，由于其低功耗和相对简单的设计，一直处于该领域的最前沿。然而，需要对这种解吸/电离源有更好的基本理解，以提高这种装置的分析能力。在这里，我们使用相对快速（2.5毫秒每光谱）的时间分辨质谱表征的时间试剂离子分布从低频LTP探针。不同的电压波形被发现严重影响放电性能，因此，离子产生。离子信号从短放电脉冲，约。40 μs时，发现显著增宽，约。10 ms，然后提取到质谱仪中。此外，较高频率的正弦波LTP产生的试剂离子的最大通量，这存在于大多数的电压波形。最后，试剂和分析物离子的时间信号进行了测量，并与特定的电离过程：质子转移和电荷转移。
New-found interest in the development of ionization sources for mass spectrometry, inspired by the advent of ambient desorption/ionization mass spectrometry, has led to a resurgence in plasma-source development and characterization. Dielectric-barrier discharges, particularly the low-temperature plasma (LTP) probe format, have been at the forefront of this field due to their low power consumption and relatively simple design. However, better fundamental understanding of this desorption/ionization source is needed to improve the analytical capabilities of such a device. Here, we use relatively fast (2.5 ms per spectrum) time-resolved mass spectrometry to characterize the temporal reagent-ion distribution from a low-frequency LTP probe. Different voltage waveforms were found to heavily influence the discharge properties and, consequently, ion production. Ion signals from short discharge pulses, ca. 40 μs, were found to be significantly broadened, ca. 10 ms, prior to extraction into the mass spectrometer. Additionally, higher frequencies of a sine-wave LTP produced the largest flux of reagent ions, which existed for most of the voltage waveforms. Finally, temporal signals for reagent and analyte ions were measured and related to specific ionization processes: proton transfer and charge transfer.