CMS Field Products, OI Analytical, 2148 Pelham Parkway, Bldg. 400, Pelham, AL, USA.
J Am Soc Mass Spectrom. 2011 Apr;22(4):612-23. doi: 10.1007/s13361-010-0067-7. Epub 2011 Feb 8.
A novel, low-cost, pixel-based detector array (described elsewhere Sinha and Wadsworth (76(2), 1) is examined using different charged particles, from electrons to hyperthermal (<100 eV) large biomolecular positive and negative ions, including keV small atomic and molecular ions. With this in mind, it is used in instrumentation design (beam profiling), mass spectrometry, and electron spectroscopy. The array detector is a modified light-sensitive charge-coupled device (CCD) that was engineered for direct charged-particle detection by replacing the semiconductor part of the CCD pixel with a conductor Sinha and Wadsworth (76(2), 1). The device is referred to as the IonCCD. For the first time, we show the direct detection of 250-eV electrons, providing linearity response of the IonCCD to the electron beam current. We demonstrate that the IonCCD detection efficiency is virtually independent from the particle energy (250 eV, 1250 eV), impact angle (45(o), 90(o)) and flux. By combining the IonCCD with a double-focusing sector field mass spectrometer (MS) of Mattauch-Herzog geometry (MH-MS), we demonstrate fast data acquisition. Detection of hyperthermal biomolecular ions produced using an electrospray ionization source (ESI) is also presented. In addition, the IonCCD was used as a beam profiler to characterize the beam shape and intensity of 15 eV protonated and deprotonated biomolecular ions at the exit of an rf-only collisional quadrupole. This demonstrates an ion-beam profiling application for instrument design. Finally, we present simultaneous detection of 140 eV doubly protonated biomolecular ions when the IonCCD is combined with the MH-MS. This demonstrates the possibility of simultaneous separation and micro-array deposition of biological material using a miniature MH-MS.
一种新型的、低成本的、基于像素的探测器阵列（详见 Sinha 和 Wadsworth (76(2), 1)），本文采用不同的带电粒子（从电子到超热（<100 eV）的大生物分子正、负离子，包括 keV 小原子和分子离子）对其进行了研究。基于这一考虑，该探测器阵列在仪器设计（束流轮廓）、质谱和电子能谱中得到了应用。该阵列探测器是一种改良的光敏电荷耦合器件（CCD），通过用导体取代 CCD 像素的半导体部分，使其能够直接检测带电粒子（Sinha 和 Wadsworth (76(2), 1)）。该设备被称为 IonCCD。我们首次展示了 250 eV 电子的直接检测，表明 IonCCD 对电子束电流具有线性响应。我们证明 IonCCD 的检测效率几乎与粒子能量（250 eV、1250 eV）、入射角（45(o)、90(o)）和通量无关。通过将 IonCCD 与 Mattauch-Herzog 几何形状的双聚焦扇形区质谱仪（MS）（MH-MS）相结合，我们实现了快速的数据采集。此外，还展示了使用电喷雾电离源（ESI）产生的超热生物分子离子的检测。另外，IonCCD 还被用作束流轮廓仪，以表征在射频-only 碰撞四极杆出口处 15 eV 质子化和去质子化生物分子离子的束形状和强度。这证明了 IonCCD 在仪器设计中的离子束轮廓应用。最后，当 IonCCD 与 MH-MS 结合使用时，我们展示了同时检测 140 eV 双质子化生物分子离子的能力。这证明了使用微型 MH-MS 同时分离和微阵列沉积生物材料的可能性。
