Imaging detector for mass spectrometry

Abstract

An imaging ion detector, consisting of an array of channel electron multipliers, a phosphor, an optical system, a vidicon camera, and a data acquisition unit, has been fitted to a Mattauch-Herzog mass spectrometer. The detector repiaces the conventional photographic plate in such instruments and has far greater sensitivity, although, in its present form, it gives lower resolution. its use in simultaneous multiple ion monitoring Is demonstrated and its application in ion kinetic energy spectrometry is foreseen. Deiiterious effects of fringing magnetic fields on the resolution of the device and saturation effects in the channeitron are discussed. The feasibility of achieving the enhanced sensitivity inherent in imaging detection in mass spectrometry is established.The photographic plate has played an important part in the practice of mass spectrometry since the earliest days. Specially prepared plates were used by Thomson (I, 2 ) in the detection system of the parabola spectrograph and similar plates are still used today on high resolution instruments (3-5) in which the arrangement of electric and magnetic fields used produces a plane of focus, as in the Mattauch-Herzog geometry (6). On the other hand, the electrical detection system used on other high and low resolution mass spectrometers has been continuously developed with respect to both its sensitivity and accuracy since the time when currents were detected using gold leaf electroscopes.

Velocity map imaging mass spectrometry

“…In both cases, all the peaks are nicely fitted in terms of two mass-dependent contributions as we expect from Eq. (7). As a consequence, as ions experience more transverse pulsed field depending on the massto-charge ratio, they are forced more off-axis.…”

“…Detector technology development has thus played a crucial role in efforts to adapt this multiplexing ion detection capability since the photographic plate was first incorporated by Thomson [3] and Aston [4] in the earliest days of the history of mass spectrometry. More recently, various types of array detectors such as microchannel plate detector arrays, multiplecollector detector arrays, and integrated array systems have been successfully applied with mass spectrometry for the simultaneous detection of multiple ions of different mass-to-charge (m/z) values [5,7,8]. On the other hand, only a few research groups [9,10] have concentrated on developing instrumentation exploiting spatial separation as well as simultaneously multiplexing different masses beyond the magnetic sector approaches.…”

Electro-Optical Ion Detectors in Mass Spectrometry Simultaneous Monitoring of All Ions over Wide Mass Ranges

“…In parallel with the development of the EOID for focal plane mass spectrometers of the Mattauch-Herzog type, similar devices were developed for use with conventional sector-type mass spectro meters (15,16,17,18). A schematic representative of this type detector, versus that implemented on a CEC type 21-490 sing le focusing mass spectrometer, is shown in Fig.…”

Novel mass spectrometry technology development for large organic particle analysis

“…In early studies, mass measurements were conned to atoms and very small molecules due to fragmentation from electron impact ionization 2 and the limited sensitivity of photographic plate detectors. 3 Aer several decades of improvements in mass spectrometry ionization technologies to obtain intact molecular ions and better detection efficiency, most organic compounds with masses less than 5000 Da can be detected. The main ionization methods used to obtain intact ions of large organic compounds (500-5000 Da) include chemical ionization, 4 eld desorption/ionization, 5 plasma desorption 6 and fast atom bombardment (FAB).…”