Fourier transform quadrupole linear ion trap mass spectrometer

描述（由申请人提供）：本阶段I SBIR项目将开发商业上可行的傅里叶变换四极杆线性离子阱MS（FT-LIT MS）。该仪器将提供优于100，000的质量分辨率，具有低ppm质量精度。由于该装置不需要大的磁体或复杂的离子注入光学器件（即，Orbitrap中的C阱），因此成本将显著低于常规FT-ICR MS或Orbitrap MS。这在Orbitrap MS中是很难做到的，可以在这个FT-LIT MS仪器中完成。由于该设备使用四极杆来限制离子，因此它提供了比Orbitrap MS更多的通用性和更大的能力。尽管许多研究人员过去已经研究了四极杆线性离子阱和3D Paul离子阱中的FT质量分析。遇到了各种常见的问题，包括信号检测中的RF干扰、空间电荷效应和电子器件的稳定性。在这项研究中，我们将解决这些问题的四极装置，一个新的离子激发方法和一个新的设计的最先进的电子设备的独特设计。在第一阶段将建造一个新的线性陷阱。该装置内部的四极捕获场将通过使用单极RF电压来驱动一对电极而实现，另一对杆保持在虚拟接地电位以用于信号检测。附加的一对RF电极位于虚拟接地电极对的外部。这些附加电极被施加与捕获RF电压相等且相反的RF电压，以抵消由捕获电极在信号检测电极对上感应的RF电压的影响。将开发带有双极/单极可切换射频电子器件的预四极组件，用于将双极多极离子导向器连接到单极检测四极组件。最后，将采用宽带圆形激励方法来最小化空间电荷效应。在第一阶段的开发中，离子阱将在高真空（10-6 mbar范围）下运行，并应达到中等分辨率（约10，000）。一旦FT-LIT MS概念得到验证，第二阶段的资金将用于开发结合联合收割机模拟和数字技术的检测电子设备，用于反馈混合和RF滤波。这将进一步减少检测信号的RF干扰，并有助于实现高检测灵敏度。在第二阶段，还将设计和制造温度调节的高稳定性（频率和振幅均低于ppm）射频发生器。线性离子阱将在超高真空（10-9 ~ 10 - 10 mbar）下工作，用于长瞬态时间高分辨探测。该FT-LIT MS可配置为紧凑型低成本、高分辨率质谱仪和/或用作混合MS仪器的高分辨率质量分析仪。

DESCRIPTION (provided by applicant): This Phase I SBIR project will develop a commercially viable Fourier Transform quadrupole Linear Ion Trap MS (FT-LIT MS). This instrument would provide mass resolution better than 100,000, with low ppm mass accuracy. Since this device does not require a large magnet or complicated ion injection optics (i.e. C-trap in an Orbitrap), the cost will considerably less than a conventional FT-ICR MS or an Orbitrap MS. Many experiments (MS/MS, IRMPD, ETD/ECD, ion-ion, ion-molecule interactions, etc.) which are very difficult to do in an Orbitrap MS could be done in this FT-LIT MS instrument. Since this device uses a quadrupole to confine ions, it offers more versatility and greater capable than an Orbitrap MS. Although many researchers have investigated FT mass analysis in quadrupole linear ion traps and 3D Paul ion traps in the past. a variety of common problems were encountered including RF interference in signal detection, space charge effects, and stability of the electronics. In this study, we will address these issues with a unique design of the quadrupole device, a new ion excitation method and a new design of state of the art electronics. A new linear trap will be constructed during Phase I. The quadrupole trapping field inside this device will be effected by using a unipolar RF voltage to drive one pair of electrodes, with the other pair of rods maintained at a virtual ground potential for signal detection. An additional pair of RF electrodes are located external to the virtual ground electrode pair. These additional electrodes are applied an RF voltage equal and opposite to the trapping RF voltage, to cancel out the effects of the RF voltage induced on the signal detection electrode pair by the trapping electrodes. A pre-quad with bipolar/unipolar switchable RF electronics will be developed for interfacing bipolar multipole ion guide to the unipolar detection quad. Finally, a broadband circular excitation method will be employed to minimize space charge effects. During Phase I development, the ion trap will be operated under high vacuum (10-6 mbar range), and medium resolution (about 10,000) should be achieved. Once the FT-LIT MS concept has been validated, Phase II funding will be used to develop detection electronics that combine analog and digital technology for feedback mixing and RF filtering. This should further reduce RF interference of the detection signal and help achieve high detection sensitivity. During Phase II, a temperature regulated highly stable (sub ppm in both frequency and amplitude) RF generator will also be designed and built. The linear ion trap will be operated under ultra high vacuum (10-9 ~ 10 -10 mbar) for long transient time high resolution detection. This FT-LIT MS can be configured as a compact low cost, high resolution mass spectrometer and/or used as a high resolution mass analyzer for hybrid MS instrumentation.