质谱基础（外文）

MASS
SPECTROMETRY
BASICS

Christopher G. Herbert
Robert A.W. Johnstone

CRC PRESS
Boca Raton London New York Washington, D.C.
Library of Congress Cataloging-in-Publication Data
Herbert, Christopher G.
Mass spectrometry basics / Christopher G. Herbert, Robert A.W. Johnstone.
p. ; cm.
Compilation of articles previously published in the series Back-to-basics.
Includes bibliographical references and index.
ISBN 0-8493-1354-6 (alk. paper)
1. Mass spectrometry. I. Johnstone, R.A.W. (Robert Alexander Walker) II. Title.
[DNLM: 1. Spectrum Analysis, Mass--Collected Works. 2. Spectrum Analysis,
Mass--Handbooks. QC 454.M3 H536m 2002]
QP519.9.M3 H47 2002
543′.0873—dc21 2002025935


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Printed on acid-free paper



Introduction
Back-to-Basics was not originally designed to be a book but, rather, a series of articles, each on a
topic dealing directly or indirectly with an aspect of mass spectrometry. Each article in the series
was intended to be a self-contained, brief (but not superficial) explanation of an area of mass
spectrometric instrumentation or theory. The aim was to provide nonexperts with enough information
to understand the major fundamental concepts underlying any chosen topic. Because basic
facts were being described, the title of the series became Back-to-Basics. For example, one of the
earliest articles covered the theory and uses of electron ionization in mass spectrometry. To ease
understanding, a complex rigorous approach was forsaken in favor of a straightforward account,
aided by many clear diagrams. By describing many of the basics of mass spectrometry and not
individual instruments per se, the series was not subject to the obsolescence that typically afflicts
books composed around a rapidly advancing subject area such as mass spectrometry. The basic
articles cover principles, which largely do not change, and therefore the articles remain useful over
longer periods of time. Of course, fashions change in mass spectrometry as in anything else. For
example, thermospray inlets for mass spectrometers have given way to more efficient ones, but the
principles underlying a thermospray device are still valid and are worth retaining on record.
Although each Back-to-Basics article is quite brief, a very short summary of each article is
provided in Appendix A for readers who want a succinct, informative account that provides a quick
working understanding of the topic.
As the number of articles increased, many of them had to be cross-referenced to other entries
in the series. Therefore, although the series began as a few articles on isolated topics, as the series
built up, the cross-referencing network increased as well. The collected articles were originally
offered in ring-binder format but, as the number of articles increased, this format became unwieldy.
Although the hardcopy versions of the Back-to-Basics series remained available to the hundreds
of regular subscribers, it was decided to post the series on the Internet for wider availability. Finally,
the articles were assembled in CD format and again made freely available by Micromass U.K.
The result of the Back-to-Basics series is an accumulation of some 50 separate but interrelated
expositions of mass spectrometric principles and apparatus. Some areas of mass spectrometry, such
as ion cyclotron resonance and ion trap instruments, have not been covered except for passing
references. This decision has not been due to any bias by the authors or Micromass but simply
reflects the large amount of writing that had to be done and the needs of the greatest proportion
of users.
For various reasons, it has been decided to close the present series of Back-to-Basics and
collect the articles in a book that can be placed on a shelf and used as a reference source. It is an
unusual book format, having a large number of rather short chapters together with a collection of
brief summaries, included as Appendix A. Thus the book will still serve the dual purposes of
describing fundamentals and additionally providing a concise synopsis of each article.

Chapter 1 Chemical Ionization (CI)....................................................................1 The Ionization Process.......................................................................................................................1 Example of the Chemical Ionization Process ...................................................................................1 Other Reagent Gases..........................................................................................................................2 Other Ionization Routes .....................................................................................................................3 Uses of CI .........................................................................................................................................4 Use of CI/EI in Tandem in GC/MS...................................................................................................4 Negative Ions.....................................................................................................................................5 Conclusion.........................................................................................................................................5 Chapter 2 Laser Desorption Ionization (LDI)......................................................7 The Ionization Process.......................................................................................................................7 Other Considerations on Laser Desorption Ionization......................................................................9 Use of a Matrix .................................................................................................................................9 Types of Laser.................................................................................................................................10 Secondary Ionization.......................................................................................................................10 Uses of Lasers.................................................................................................................................11 Conclusion.......................................................................................................................................12 Chapter 3 Electron Ionization (EI) ...................................................................13 The Ionization Process.....................................................................................................................13 Mass-To-Charge Ratio (m/z)