SGER: Charge Amplifier for Biological Mass Spectrometry

John C. Price获得了一笔拨款，用于开发一种低温参数电荷放大器，该放大器具有提高灵敏度的生物质谱应用。目前生物质谱的一个主要趋势是通过使用电喷雾和激光解吸电离技术将质谱扩展到兆道尔顿的质量范围。在这个质量范围内，许多对生物技术、医学诊断和分子生物学具有重要意义的研究都是可能的，包括完整病毒的鉴定和蛋白质/核酸复合物的研究。软电离技术产生具有数万至数千个基本电荷和宽电荷分布的兆道尔顿离子。现有的质谱仪只能测量质量电荷比，在许多情况下无法分辨或识别单个电荷状态，因此多次充电严重限制了质量分辨率。这个问题可以通过电荷检测质谱（CD-MS）来解决，这是一种离子通过连接到敏感电荷放大器的法拉第管的技术，这样就可以直接测量单个离子的电荷。然而，CD-MS受限于现有电荷放大器的低分辨率，不超过50个电子的均方根（e- rms）。本研究项目将开发一种新型的低温参量电荷放大器，提高灵敏度，用于CD-MS应用。

A grant has been awarded to John C. Price for the development of a cryogenic parametric charge amplifier with improved sensitivity for biological mass spectrometry applications. A current major trend in biological mass spectrometry is extension to the megadalton mass range through the use of electrospray and laser desorption ionization techniques. Many studies of importance to biotechnology,medical diagnosis, and molecular biology are possible in this mass range,including the identification of intact viruses and study of protein/nucleic acid complexes. Soft ionization techniques produce megadalton ions with tens to thousands of elementary charges and a broad charge distribution. Existing mass spectrometers only measure the mass-to-charge ratio,and in many situations it is not possible to resolve or identify the individual charge states,so that multiple charging places severe limits on mass resolution. This problem can addressed by charge detection mass spectrometry (CD-MS), a technique in which ions are passed through a Faraday tube connected to a sensitive charge amplifier, so that the charge may be directly measured on individual ions. However, CD-MS is limited by the poor resolution of existing charge amplifiers, not better than about 50 electrons root-mean-square (e- rms). This research project will develop a new type of cryogenic parametric charge amplifier with improved sensitivity for CD-MS applications.