STOCHASTIC FT ION CYCLOTRON RESONANCE MASS SPECTROMETRY

我们建议升级Nicolet FTMS-1000傅里叶变换质量 从光谱仪到带有8特斯拉磁铁的Nicolet FTMS-2000。现在 真空系统和小车、电池组装和安装以及真空泵 更换新版本，励磁放大器将升级 至更高的输出电压。现有的控制台和数据系统将 保留。新的系统将同时提供定性和定量的 改进。最重要的新功能将是 高质量分辨率的可靠的气相色谱/FT/MS； 除特殊情况外，不能在FTMS-1000上进行实验 精选样本。此外，一些数量上的改进也是如此 提供质量上的新能力：(A)快速更换样品 (10分钟，而FTMS-1000目前需要最多2小时)；(B) 由于离子，提高了信噪比(至少是5倍) 高压地层，低压探测；(C)强化 由于探测器压力较低，分辨率(至少为5倍)； (D)两英寸的样品池而不是一英寸的样品池，从而使 信噪比和质量分辨率翻倍，以及改进 由于减少库仑加宽而形成的线条形状；(E)网状而不是实心 电池板，在GC过程中提供更有效的泵浦电导 和/或改变样品；(F)降低检测器的压力，允许 用于激光解吸/电离过程中的精确质量测定 实验。磁场越大，信噪比越高 (2.66x)和质量分辨率(2.66x)，并减少数据采集时间(7.1x)。 分时“量身定制”激励(即“随机”激励)将 为FT/MS开发，提供软件-可互换：(A)扁平 用于精确同位素比测量的激发功率，(B)加窗 用于提高动态范围或高质量分辨率的MS/MS的激励， 以及(C)第一个同时进行多离子监测的能力。这些 方法将应用于合成和合成的化合物的质谱分析 天然药物和代谢物。

We propose to upgrade our Nicolet FTMS-1000 Fourier transform mass spectrometer to a Nicolet FTMS-2000 with 8 tesla magnet. The present vacuum system and cart, cell assembly and mount, and vacuum pumps will be exchanged for new versions, and the excitation amplifier will be upgraded to higher output voltage. The existing console and data system will be retained. The new system will provide both qualitative and quantitative improvements. The most important new feature will be the capability for reliable gas chromatography/FT/MS at high mass resolution; those experiments cannot be performed on the FTMS-1000, except for specially chosen samples. In addition, several quantitative improvements are so great as to offer qualitatively new capability: (a) rapid sample changing (10 min compared to up to 2 hours presently required on the FTMS-1000); (b) improved signal-to-noise ratio (at least a factor of 5), due to ion formation at high pressure with detection at low pressure; (c) enhanced resolution (at least a factor of 5) due to lower pressure at the detector; (d) two-inch sample cell rather than one-inch, resulting in a doubling of signal-to-noise ratio and doubling of mass resolution, as well as improved line shape due to reduced Coulomb broadening; (e) mesh rather than solid cell plates, providing for more efficient pump-down conductance during GC and/or on changing samples; (f) reduced pressure at the detector, allowing for exact mass determination during laser desorption/ionization experiments. The higher magnetic field will increase signal-to-noise ratio (2.66X) and mass resolution (2.66X) and reduce data acquisition time (7.1X). Time-shared "tailored" excitation (i.e., "stochastic" excitation) will be developed for FT/MS, providing software-interchangeable: (a) flat excitation power for precise isotope-ratio measurement, (b) windowed excitation for increased dynamic range or MS/MS with high mass resolution, and (c) the first simultaneous multiple-ion monitoring capability. These methods will be applied toward mass spectrometric analysis of synthetic and natural drugs and metabolites.