White F M, Marto J A, Marshall A G
Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Florida State University, Tallahassee 32310, USA.
Rapid Commun Mass Spectrom. 1996;10(14):1845-9. doi: 10.1002/(SICI)1097-0231(199611)10:14<1845::AID-RCM749>3.0.CO;2-#.
An external source 7 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer offers three main novel features. First, a 9-way ion-source cross allows for mounting of up to three ionization sources simultaneously, thereby minimizing 'downtime' for changing ion sources. Second, an electrostatic (wire-in-cylinder) ion guide transports the ions approximately 1.5 m from the ion source to the ion trap for mass analysis, through a large magnetic field gradient. Third, the system operates from a modular data system described elsewhere in this issue. Luteinizing hormone-releasing hormone (LH-RH) matrix-assisted laser desorption/ionization (MALDI) FTICR positive-ion mass spectra exhibit signal-to-noise ratio greater than 1000:1 and mass resolving power, m/delta m 50% > 100,000. Laser-induced fragmentation of bradykinin demonstrates the ability of the ion guide to transmit both molecular and fragment ions simultaneously. Ultra-high resolution (average resolving power approximately 400,000) was achieved for poly(ethylene glycol) of specified number-average molecular weight, Mn approximately 3400. Future installation of an electrospray source to the ion-source cross should allow for better characterization of the performance of the ion guide.
一台外部源7T傅里叶变换离子回旋共振（FTICR）质谱仪具有三个主要的新颖特性。首先，一个9路离子源交叉装置允许同时安装多达三个电离源，从而将更换离子源的“停机时间”降至最低。其次，一个静电（圆柱内导线）离子导向装置将离子从离子源传输约1.5米至离子阱进行质量分析，穿过一个大的磁场梯度。第三，该系统由本期其他地方描述的模块化数据系统运行。促黄体生成素释放激素（LH-RH）基质辅助激光解吸/电离（MALDI）FTICR正离子质谱显示信噪比大于1000:1，质量分辨率，m/Δm 50%>100,000。缓激肽的激光诱导碎裂证明了离子导向装置同时传输分子离子和碎片离子的能力。对于指定数均分子量Mn约为3400的聚乙二醇，实现了超高分辨率（平均分辨率约为400,000）。未来在离子源交叉装置上安装电喷雾源应能更好地表征离子导向装置的性能。
