Multi‐turn time‐of‐flight mass spectrometers with electrostatic sectors

Abstract

The mass resolution of a time-of-flight (TOF) mass spectrometer is directly proportional to its total flight pathlength. Multi-turn or multi-passage ion optical geometries are necessary to obtain fight distances of sufficient length within reasonable size limitations. We have investigated ion optics for a multi-turn TOF mass spectrometer with electrostatic sectors. The concept of 'perfect' focusing conditions is introduced. Furthermore, a new type of multi-turn TOF mass spectrometer, the MULTUM Linear plus, was developed. It consists of four cylindrical electric sectors and 28 electric quadrupole lenses. It has a vacuum chamber 60 × 70 × 20 cm in size. Mass resolution is demonstrated to increase according to the number of ion cycles. A mass resolution of 350 000 (m/z = 28, FWHM) was achieved after 501.5 cycles. The MULTUM Linear plus analyzer is not simple, however; 28 electric quadrupole lenses are used. In order to reduce the number of ion optical parts, an improved multi-turn TOF mass spectrometer, the MULTUM II, consisting of only four toroidal electric sectors, was also developed. The possibility of tandem mass spectrometric applications using multi-turn TOF mass spectrometers is also discussed.

High Spatial Resolution Laser Desorption/Ionization Mass Spectrometry Imaging of Organic Layers in an Organic Light-Emitting Diode

“…9) A mass image in a 200 µm diameter area was measured with a spatial resolution of 4 µm over 20-shots using a laser with a 12 Hz repetition rate. 9) Recently, the stigmatic imaging mass spectrometer 'MULTUM-IMG2' 10,11) developed at Osaka University has advanced the stigmatic MSI with a novel ion-extraction method 10) and the use of the multi-turn type ion optical system MULTUM II, 12) which has achieved high mass resolution by providing an essentially in nite ion ight path by focusing the ions in a gure-eight orbit.…”

“…is system is based on the MULTUM II multi-turn ion optical system using electrostatic sectors. 12) A Nd:YLF laser (Newport, CA, USA, wavelength λ=349 nm) was used and its radius was xed to 20 µm. e OLED device for evaluation was set directly on the target plate in the area where the target plate was sunken 1 mm in depth.…”

Miniaturized Mass Spectrometer in Analysis of Greenhouse Gases: The Performance and Possibilities

“…The proposed systems are listed as follows: Figure 1 shows the development history of multi-turn TOF mass spectrometers at Osaka University. We designed and constructed the first multi-turn TOF mass spectrometer "MULTUM Linear plus" as a laboratory model for cometary exploration (Matsuo et al, 1999;Toyoda et al, 2000;Toyoda et al, 2003). The system consists of four discrete units, each comprised of an electrostatic quadrupole lens, a cylindrical electrostatic sector and an electrostatic quadrupole lens.…”

Inductively Coupled Plasma Zoom–Time-of-Flight Mass Spectrometry

“…In the last 15 years, multi-turn and multipass instruments have reported mass resolution in the high tens-of-thousands, approaching the lower end of resolution for Fourier-transform systems [7][8][9][10][11][12]. Yet, single-reflectron TOFMS instruments are the most common because they are useful for the study of transient events such as are produced by laser ablation [13][14][15][16], chromatography [17][18][19], and electrothermal (furnace) vaporization [20,21].…”