Laughlin Brian C, Mulligan Christopher C, Cooks R Graham
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
Anal Chem. 2005 May 1;77(9):2928-39. doi: 10.1021/ac0481708.
A miniature cylindrical ion trap mass spectrometer featuring an atmospheric pressure interface allowing atmospheric pressure chemical ionization and electrospray ionization is described together with its analytical performance characteristics. The vacuum system, ion optics, mass analyzer, control electronics system, and detection system have all been designed and built in-house. The design is based upon a three-stage, differentially pumped vacuum system with the instrument capable of being interfaced to many types of atmospheric pressure ionization sources. Ions are transferred through home-built ion optics, and instrument control is achieved through custom-designed electronics and LabView control software. Corona discharge ionization and electrospray ionization sources are implemented and used to allow the analysis of both gaseous- and solution-phase samples during the characterization of the instrument. An upper mass/charge limit of approximately 450 Th with unit resolution was achieved using a 2.5-mm-internal radius cylindrical ion trap as the mass analyzer. The specificity of the instrument can be increased by employing the MS/MS capabilities of the ion trap and has been demonstrated for nitrobenzene. Limits of detection for the trace analysis in air of the chemical warfare agent simulant methyl salicylate (1.24 ppb) and for nitrobenzene (629 pptr) are achieved. The dynamic range of the instrument is currently limited to approximately 2 orders of magnitude by saturation of the detection electronics. Isolation and collision-induced dissociation efficiencies in MS/MS experiments both greater than 50% are reported. Electrospray/nanospray data are presented on solutions including 100 microM (D,L)-arginine, 10 microM (-)-ephedrine, and 10 microM lomefloxacin.
介绍了一种具有大气压接口的微型圆柱形离子阱质谱仪，该接口允许大气压化学电离和电喷雾电离，并阐述了其分析性能特征。真空系统、离子光学系统、质量分析器、控制电子系统和检测系统均为内部设计和构建。该设计基于三级差动抽气真空系统，仪器能够与多种类型的大气压电离源连接。离子通过自制的离子光学系统传输，仪器控制通过定制设计的电子设备和LabView控制软件实现。实现了电晕放电电离和电喷雾电离源，并在仪器表征过程中用于分析气相和液相样品。使用内径为2.5毫米的圆柱形离子阱作为质量分析器，实现了约450 Th的单位分辨率的质荷比上限。通过利用离子阱的串联质谱功能可以提高仪器的特异性，这已在硝基苯的分析中得到证明。实现了对化学战剂模拟物水杨酸甲酯在空气中痕量分析的检测限（1.24 ppb）和对硝基苯的检测限（629 pptr）。目前，由于检测电子设备的饱和，仪器的动态范围限制在约2个数量级。报告了串联质谱实验中的分离效率和碰撞诱导解离效率均大于50%。给出了包括100 microM（D，L）-精氨酸、,10 microM（-）-麻黄碱和10 microM洛美沙星的溶液电喷雾/纳米喷雾数据。
