Quadrupole Mass Spectrometry and Its Applications

Preface

Principal symbols

Chapter I. Introduction

References

Chapter II. Principles of operation

A. The quadrupole field


1 The geometry


2 The applied potential


3 The equations of motion


4 The ion trajectories

B. The mass filter


1The stability diagram


2 The resolution


3 The mass filter aperture


4 The mass filter acceptance


5 Computed performance


6 Ion exit


7 The rectangularly driven mass filter


8 A high-resolution device

C. The monopole


1 Conditions for ion transmission


2 Resolution


3 Mass scanning


4 Computed performance


5 Ion energy


6 Geometrical variations


7 Apparent advantages and disadvantages

D. The quadrupole ion trap


1 Conditions for ion trapping


2 Mass-selective ion detection


3 Mass-selective ion storage


4 Computer simulations


5 Novel features

E. Exact focusing devices

F. The oscillatory field time-of-flight spectrometer

G. Static quadrupole devices

References

Chapter III. Analytical theory

A. The Hill equation

B. The Mathieu equation

C. The complete solution

D. Auxiliary fields

E. Special cases

References

Chapter IV. Numerical calculations

A. Numerical integration

B. Matrix methods


1 Matrix representation


2 Phase-space dynamics

References

Chapter V. Fringing fields and other imperfections

A. Fringing fields


1 The mass filter


2 The monopole

B. Systematic field faults


1 The analytical approach


2 Computer simulation


3 Experimental evidence


4 Round rods


5 Field distortions and the monopole

References

Chapter VI. The mass filter: design and performance

A. Basic considerations of mass range and resolution

B. Field imperfections and their effect on performance


1 Mechanical misalignments of the rods


2 Contamination of the rods


3 The use of circular rods to approximate hyperbolic fields

C. The ion source


1 Design and construction


2 Alignment of the source

D. Ion detection


1 The Faraday cup


2 The electron multiplier


3 High pressure limit of operation

E. Instrument sensitivity


1 Dependence on resolution


2 Dependence on mass


3 The delayed d.c. ramp

F. Operation with non-sinusoidal fields

G. Electrical power supplies

References

Chapter VII. The monopole: design and performance

A. Introduction

B. Ion oscillations in a monopole

C. Ion entrance and exit

D. Mechanical construction of the monopole

E. The power supply


1 Sweep unit


2 Rf unit

F. Comparison of the experimental observations with theoretical expectations


1 Mass scale and dispersion


2 Scanning methods and extended mass range


3 Peak width and peak shape


4 Resolution and peak separation


5 Sensitivity

G. Effect of a high pressure in the monopole section

H. Negative ions

I. Power consumption

J. Conclusions

References

Chapter VIII. Quadrupole ion traps

A. Introduction

B. The three-electrode ion trap. Construction and instrumentation


1 The electrodes


2 Ion creation


3 The rf power supply


4 Ion detection

C. Other forms of ion trap


1 The six-electrode trap


2 The storage-ring trap


3 The static ion trap

D. Survey of applications of ion traps


1 Mass spectrometric applications


2 The storage of microparticles


3 The quadrupole ion storage source (quistor)

E. Experimental and theoretical aspects of ion containment


1 Ion loss processes


2 A theoretical model of ion trapping


3 Space charge and ion kinetic energies

References

Chapter IX. Time-of-flight spectrometers

A. Introduction

B. Principle of operation

C. Ion displacement

D. Arrival time

E. Resolution

F. Experimental results

G. Proposed new design

H. New modes of operation

I. Conclusions

References

Chapter X. Applications in atomic and molecular physics

A. General applications


1 Vacuum technology


2 Surface studies


3 Reaction studies involving solids or surfaces


4 Gas phase studies

B. Special applications

l The use of r f fields for "beam guides"


2 Applications of charged-particle traps

References

Chapter XI. Applications to upper atmosphere research

A. Early history of mass spectrometric measurements in the upper atmosphere

B. The upper atmosphere of the earth

C. Techniques of in situ measurements


1 Neutral gas analysis


2 Ion analysis

D. Recent quadrupole applications and developments

References

Chapter XII. Applications to gas chromatography

A. Introduction

B. Gas chromatography-quadrupole mass spectrometry instrumental developments


1 Resolution, mass range and peak shapes of the quadrupole


2 Gas Chromatograph interfacing


3 Sensitivity and dynamic range


4 Electronic control requirements and capabilities

C. Automation

D. New techniques


1 Stable isotope mass fragmentography


2 Chemical ionization


3 Capillary columns

E. Conclusion

References

Chapter XIII. Medical and environmental applications

A. Medical applications


1 Respiratory gas analysis


2 Blood gas analysis


3 Drug detection and analysis


4 "Fingerprinting" of bacteria

B. Environmental monitoring


1 Detection of pollutants in air


2 Water analysis


3 Technological applications

C. Conclusions

Notes added in proof

References

Appendices

Appendix A. Parameters characterizing the acceptance ellipses for the mass filter with no fringing fields

Appendix B. Approximate acceptance ellipse parameters for the mass filter for transmission at 50% of the initial phases in the presence of fringing fields of various lengths

Appendix C. Paired values of a and q satisfying the conditions β(a, q) = l/d;β(-a,-q) = p/d for 2 < d < 13, p ≤ d

Appendix D. Coefficients from C0 to C6 used in the analytical solution to the equation of motion in the mass filter

Appendix E. An example of a simple computer program for calculating ion trajectories by numerical (Runge—Kutta) integration of the Mathieu equation. The program is written in Fortran IV G

Appendix F. List of quadrupole patents

Index