Characterization of Direct-Current Atmospheric-Pressure Discharges Useful for Ambient Desorption/Ionization Mass Spectrometry
Characterization of Direct-Current Atmospheric-Pressure Discharges Useful for Ambient Desorption/Ionization Mass Spectrometry
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DOI：
10.1016/j.jasms.2008.12.020
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发表时间：
2009-05-01
影响因子：
3.2
通讯作者：
Hieftje, Gary M.
中科院分区：
文献类型：
--
作者：
Shelley, Jacob T.;Wiley, Joshua S.;Hieftje, Gary M.
两种相对较新的常压电离源，实时直接分析（DART）和流动大气压余辉（FAPA），利用直流、大气压放电产生试剂离子，用于样品的直接电离。尽管乍一看这两种电离源似乎相似，但一项基础研究揭示了它们的不同之处。具体而言，发现DART是在电晕到辉光转变（C - G）放电模式下运行，而FAPA是在辉光到电弧转变（G - A）放电模式下运行。基于四个因素对这两种放电的特性进行了评估：试剂离子的产生、对一种模型分析物（二茂铁）的响应、用于解吸和电离的气体的红外（IR）热成像以及空间发射特性。G - A放电比C - G放电产生更丰富且种类更多的试剂离子。此外，对于二茂铁，这两种放电产生了不同的加合物和信号强度。还发现，从放电室出来的气体，G - A放电和C - G放电分别达到最高235℃和55℃。最后，这两种放电的空间分辨发射图谱显示，N₂⁺和O（I）存在明显差异。这些发现表明，FAPA和DART所使用的放电从根本上是不同的，并且在常压解吸/电离质谱（ADI - MS）中应该有不同的最佳应用。（《美国质谱学会杂志》2009年，20卷，837 - 844页）（C）2009年由爱思唯尔公司代表美国质谱学会出版
Two relatively new ambient ionization source, direct analysis in real time (DART) and the flowing atmospheric-pressure afterglow (FAPA), Use direct current, atmospheric-pressure discharges to produce reagent ions for the direct ionization of a sample. Although at a first glance these two sources appear similar, a fundamental study reveals otherwise. Specifically, DART was found to operate with a corona-to-glow, transition (C-G) discharge whereas the FAPA was found to operate with a glow-to-arc transition (G-A) discharge. The characteristics of both discharges were evaluated on the basis Of four factors: reagent-ion production, response to a model analyte (ferrocene), infrared (IR) thermography of the gas used for desorption and ionization, and spatial emission characteristics. The G-A discharge produced a greater abundance and a wider variety of reagent ions than the C-G discharge. In addition, the discharges yielded different adducts and signal strengths for ferrocene. It was also found that the gas exiting the discharge chamber reached a maximum of 235 degrees C and 55 degrees C for the G-A and C-G discharges, respectively. Finally, spatially resolved emission maps of both discharges showed clear differences for N-2(+) and O(I). These findings demonstrate that the discharges Used by FAPA and DART are fundamentally different and should have different optimal applications for ambient desorption/ionization mass spectrometry (ADI-MS). (J Am Soc Mass Spectrom 2009, 20, 837-844) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry