Xu Wei, Charipar Nicholas, Kirleis Matthew A, Xia Yu, Ouyang Zheng
Weldon School of Biomedical Engineering, Department of Chemistry, and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, Indiana 47907.
Anal Chem. 2010 Aug 1;82(15):6584-6592. doi: 10.1021/ac101002t.
The discontinuous atmospheric pressure interface (DAPI) has allowed the transfer of ions from atmospheric pressure ionization sources to an ion trap mass analyzer in hand-held mass spectrometers with miniature pumping systems at transfer efficiencies high enough for proper chemical analysis. The DAPI potentially would allow a significant enhancement to the mass analysis efficiency of laboratory-scale mass spectrometers, which have pumping systems of much larger capacities. A laboratory-scale mass spectrometer with a DAPI-RIT (rectilinear ion trap)-DAPI configuration has been developed to explore this possibility. The gas dynamic effects on ion trapping and mass analysis have been studied at various conditions. A pulsed nanoelectrospray ionization source synchronized with the DAPI has been implemented to improve the sample usage efficiency as well as to adjust the number of ions to be trapped for MS analysis, so that space charge effects can be avoided. Single-scan spectra of peptides were recorded with an ionization time as short as 1 mus, corresponding to an analyte consumption of several attomoles. The simplicity of application of the DAPI for performing ion/molecule and ion/ion reactions has also been demonstrated with proton transfer and electron transfer dissociation reactions with peptides.
间断大气压接口（DAPI）已实现了在配备微型抽气系统的手持式质谱仪中，将离子从大气压电离源转移至离子阱质量分析器，其转移效率足以满足适当化学分析的要求。DAPI 有可能显著提高实验室规模质谱仪的质量分析效率，这类质谱仪具有容量大得多的抽气系统。已开发出一种具有 DAPI-直线离子阱（RIT）-DAPI 配置的实验室规模质谱仪，以探索这种可能性。已在各种条件下研究了气体动力学对离子捕获和质量分析的影响。已采用与 DAPI 同步的脉冲纳米电喷雾电离源，以提高样品使用效率，并调整用于质谱分析的捕获离子数量，从而避免空间电荷效应。肽的单扫描光谱在短至 1 微秒的电离时间下记录，这对应于几个阿托摩尔的分析物消耗量。通过与肽的质子转移和电子转移解离反应，也证明了 DAPI 在进行离子/分子和离子/离子反应方面应用的简便性。
