摘要:

The title of this special journal issue, “Advances in Time-of-Flight Mass Spectrometry”, implies that in recent years there has been progress in the subject area. Yet, without an account of what happened in the past, that is a history, you cannot appreciate the rapid and sophisticated advancements that took place in this field during the last ten years. After delving into the history of time-of-flight mass spectrometry (TOFMS), I thought it important to share some of the historical highlights of TOFMS instrumental development as a prelude to the other papers in this special journal issue. The purpose of this essay is to acquaint unfamiliar readers with the history of TOFMS instrumentation and its application to chemical research.

ISSN:1073-9149    

DOI:10.1080/10739148708543625

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Advantages and disadvantages of time-of-flight mass spectrometers are discussed as compared to laterally dispersive systems. Fundamental relations for the design of such systems are presented as well as examples for different applications.

ISSN:1073-9149    

DOI:10.1080/10739148708543626

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Velocity compaction is an ion focusing principle applicable to pulsed ion source time-of-flight mass spectrometers, and is designed for achieving improved mass resolution. A quantitative view of the effect of velocity compaction focusing on a transiting iso-mass ion packet is shown. Derived equations relating the various physical dimensions of the mass spectrometer and the method of ion extraction with the time-dependent accelerating voltage required to effect velocity compaction are presented. Predicted spectra and mass resolution based on computer simulation studies are compared with actual performance in the lower mass range up to about 300 amu. The choice of initial ion temperature in the source region affects the overall mass resolution as expected, but the effect is markedly reduced by the velocity compaction focusing section. Expected mass spectra for temperatures as high as 5000 K have been obtained and indicate that unit mass separation at mass 4000 amu is possible at this extreme value.

ISSN:1073-9149    

DOI:10.1080/10739148708543627

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new generation252Cf-plasma desorption time-of-flight mass spectrometer has been developed and placed into operation. The new features address particular requirements for high-mass studies but the overall design has been to markedly increase the flexibility for carrying out a variety of different kinds of experiments. The new features include a provision for controlling the252Cf source-target and target-acceleration grid distance, an IR diode array for identification and precise positioning of targets, and different configurations of the field-free and ion detector region for post-acceleration, metastable ion analysis, and velocity focusing. Improvements have also been made in the data acquisition and analysis programs specifically for high-mass studies in order to obtain more accurate masses and a more complete picture of the complete ion distribution by generating “digital difference” mass spectra.

ISSN:1073-9149    

DOI:10.1080/10739148708543628

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

252Cf plasma desorption mass spectrometry (PDMS) as utilized in the BIO-ION instruments is described. The sensitivity of the technique is investigated for varying amounts of bovine insulin. The results show accurate mass assignment for pmole amounts of sample.

ISSN:1073-9149    

DOI:10.1080/10739148708543629

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Conversion of Wiley-McLaren type TOF instruments for laser desorption is described, including laser optics, timing circuitry, postacceleration detection for high mass and data acquisition. Results are shown to illustrate signal averaging capabilities, detection limits and high mass measurements.

ISSN:1073-9149    

DOI:10.1080/10739148708543630

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A system is described that uses laser desorption as a means of volatilizing small, thermally-labile biomolecules into the gas phase as neutral species. The desorbed molecules are then entrapped in a pulsed supersonic jet expansion of CO2and swept into a differentially pumped time-of-flight mass spectrometer. Laser induced R2PI at 280 nm or 266 nm through the π-π*transition is used to ionize these species softly at modest input energy.

ISSN:1073-9149    

DOI:10.1080/10739148708543631

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

UV laser-induced surface ionization with prism internal reflection is demonstrated to be a useful ion source for the Time-of-Flight mass spectrometer (TOF-MS). Spraying aniline (93 amu) on the prism surface and using 2 ns UV laser pulses, mass resolutions of 3,900 and 11,000 have been achieved in a linear TOF-MS and in a reflectron TOF-MS, respectively. Theoretical calculations indicate that mass resolution of over one million is possible, if a picosecond laser and appropriate electronics are employed.

ISSN:1073-9149    

DOI:10.1080/10739148708543632

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Details of the novel method of laser desorption with a low powered IR-laser and resonance-enhanced multiphoton ionization (REMPI) combined with a high-resolution Reflectron-Time-of-Flight (RETOF) mass spectrometer are explained. Different features of the method are discussed. Some results of mass spectrometric investigations of biomolecules are shown.

ISSN:1073-9149    

DOI:10.1080/10739148708543633

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Some recent improvements to the Manitoba linear time-of-flight mass spectrometer are reviewed. A new data system gives greatly improved performance. A detector assembly with a small 45° ion mirror and separate detectors for neutral and charged particles has been added. In conjunction with the new data system, it enables measurement of correlations between neutral and charged fragments resulting from unimolecular decay in the flight tube.

ISSN:1073-9149    

DOI:10.1080/10739148708543634

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor