A STUDY OF ION-MOLECULE REACTIONS IN A DYNAMIC REACTION CELL TO IMPROVE...

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A STUDY OF ION-MOLECULE REACTIONS IN A DYNAMIC REACTION CELL TO IMPROVE ELEMENTAL ANALYSIS WITH INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY

DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate School of
The Ohio State University
By
Deanna M. Rago Jones

TABLE OF CONTENTS
Page
Abstract.......................................................................................................................... ii
Dedication...................................................................................................................... vi
Acknowledgments.......................................................................................................... vii
Vita................................................................................................................................. viii
List of Tables.................................................................................................................. xv
List of Figures................................................................................................................ xxii
Chapters:
1. Introduction................................................................................................................ 1
1.1 Introductions......................................................................................................... 1
1.2 Inductively Coupled Plasma Mass Spectrometer.................................................. 6
1.3 Previous approaches to minimize or account for spectral overlaps...................... 6
1.4 Development of the Inductively Coupled Plasma Dynamic Reaction Cell
Mass Spectrometer...................................................................................................... 8
1.5 Previous investigations of ion-molecule reactions for ICP-MS............................ 11
1.6 Inductively Coupled Plasma Dynamic Reaction Cell Mass Spectrometer
(ICP-DRC-MS) with quadrupole reaction cell........................................................... 12
1.7 Experimental......................................................................................................... 16
1.7.1 Instrumental details......................................................................................... 16
1.7.2 Experimental details........................................................................................ 18
1.8 Ion-molecule reaction data.................................................................................... 21
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1.8.1 Ion signal versus mass.................................................................................... 21
1.8.2 Ion signal versus reaction cell gas flow rate plots.......................................... 22
1.8.3 Ion signal versus RPq plot.............................................................................. 26
1.9 Dissertation organization...................................................................................... 30
2. Reactions between background ions (polyatomic and doubly charged ions, N+,
O+, Ar+) and NH3........................................................................................................ 37
2.1 Purpose.................................................................................................................. 37
2.2 Spectral Overlap Ions............................................................................................ 37
2.3 Experimental details and data analysis................................................................. 42
2.4 Behavior of background ions from DIH2O and NH3 at m/z 1 to 80 amu............ 43
2.4.1 Reaction rates for the most intense background ions from a deionized
H2O sample and NH3............................................................................................... 45
2.4.2 Behavior of background ion signal with NH3 at masses isobaric with
elemental ions........................................................................................................... 64
2.5 New product ions from DI H2O ions and ammonia gas........................................ 69
2.5.1 Identifying product ions.................................................................................. 69
2.5.2 Behavior of masses 18, 35, 52 and 69............................................................. 73
2.6 Spectral overlaps resulting from concomitant species.......................................... 78
2.6.1 Reactions between Argide ions (ArM+) and NH3........................................... 80
2.6.1.1 Confirming the presence of Argide (ArM+) ions...................................... 81
2.6.1.2 Calculating the rates of reactions of Argide (ArM+) ions with NH3......... 87
2.6.2 Reactions between doubly charged ions (M2+) and NH3................................ 92
2.6.2.1 Second ionization potentials and doubly charged ion signals in the
vented mode.......................................................................................................... 92
2.6.2.2 Loss of signal rates for doubly charged ions with NH3............................ 95
2.6.3 Reactions between oxides (MO+) and NH3..................................................... 99
2.7 Conclusions........................................................................................................... 116
3. Reactions between elemental ions and NH3............................................................... 121
3.1 Purpose.................................................................................................................. 121
3.2 Introduction........................................................................................................... 123
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3.3 Study of the Au+ internal standard........................................................................ 126
3.4 Loss of elemental ion signal/relative reaction rates.............................................. 135
3.4.1 Plots of Elemental Ion Signals versus NH3 flow rate..................................... 135
3.4.2 Rate of elemental ion signal change by linear fit............................................ 141
3.4.3 Rate of elemental ion signal change by two-point fit..................................... 143
3.4.4 Rate of elemental ion signal change by ratio of M+ ion signal to a sum of
all M+ containing ion signals.................................................................................... 146
3.4.5 Compare rates of ion signal change to rates found in the literature................ 156
3.5 A study of the products of reactions between elemental ions and NH3................ 160
3.5.1 Plots of elemental ion and product ion signals at select NH3 flow rates........ 160
3.5.2 Charge transfer reactions between elemental ions and NH3........................... 180
3.5.3 Clustering associations between elemental ions and NH3.............................. 196
3.5.3.1 Main Group Elements............................................................................... 199
3.5.3.1.1 Columns I and II of the Periodic Table............................................... 201
3.5.3.1.2 Columns XIII through XVI of the Periodic Table.............................. 207
3.5.3.1.3 Non-reactive ions, Li+, B+ and Si+...................................................... 211
3.5.3.1.4 Ratio of cluster product ion signal to vented mode elemental ion
signal.................................................................................................................. 214
3.5.3.1.5 Ratio of cluster product ion signal to pressurized mode elemental
ion signal............................................................................................................ 217
3.5.3.2 Transition Metals Group........................................................................... 224
3.5.3.2.1 Plots of ion signal versus NH3 flow rate............................................. 227
3.5.3.2.2 Ratio of cluster product ion signal to vented mode elemental ion
signal for transition metals................................................................................. 237
3.5.3.2.3 Ratio of product ion signal to elemental ion signal (pressurized
mode) for transition metals................................................................................ 240
3.5.4 Condensation reaction between elemental ions and NH3............................... 242
3.5.4.1MNH+ category.......................................................................................... 245
3.5.4.1.1 Condensation product ion distribution for MNH+ category
elemental ions..................................................................................................... 246
3.5.4.1.2 Secondary condensation reactions creating MN+ and M(NH)2
+......... 252
3.5.4.1.3 Ratio of product ion signal to elemental ion signal (vented mode).... 256
3.5.4.1.4 Ratio of product ion signal to bare elemental ion signal (pressurized
mode).................................................................................................................. 260
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3.5.4.2 MNH2
+ category........................................................................................ 262
3.5.4.2.1 Ratio of product ion signal to bare elemental ion signal in the
vented mode....................................................................................................... 266
3.5.4.2.2 Ratio of product ion signal to elemental ion signal in the
pressurized mode................................................................................................ 267
3.5.4.3 MNH3
+ category........................................................................................ 268
3.5.4.3.1 Ratio of product ion signal to elemental ion signal in the vented
mode................................................................................................................... 271
3.5.4.3.2 Ratio of product ion signal to elemental ion signal in the
pressurized mode................................................................................................ 272
3.6 Conclusions........................................................................................................... 275
4. Elemental and product ion behavior through adjustments of the reaction cell
quadrupole bandpass.................................................................................................. 283
4.1 Purpose.................................................................................................................. 283
4.2 Introduction........................................................................................................... 283
4.2.1 The dynamic reaction cell quadrupole bandpass............................................ 283
4.2.2 Prevention of NH3 clustering and condensation product ions........................ 289
4.3 Bandpass (RPq) rejection of NH3 cluster and condensation product ions............ 293
4.4 Elemental ion signal behavior versus Rpq............................................................ 299
4.4.1 Elements that undergo clustering reactions predominantly............................ 301
4.3.2 Elements that undergo condensation reactions............................................... 303
4.5 Improvement in analyte/overlap ion ratio............................................................. 309
4.5.1 Using the DRC bandpass................................................................................ 309
4.5.2 Kinetic energy discrimination......................................................................... 312
4.6 Conclusions.......................................................................................................... 317
5. Reactions between elemental and select background (DI H2O source) ions with
ethylene (C2H4) and comparisons to reactions with ammonia................................... 319
5.1 Purpose.................................................................................................................. 319
5.2 Introductions......................................................................................................... 319
5.3 Background ions produced from a Deionized H2O blank and their reactions
with C2H4.................................................................................................................... 322
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5.3.1 DI H2O Spectra - new product ions................................................................. 322
5.3.2 Reaction rates for select background spectral overlap ions............................ 331
5.4 Utility of C2H4 for detection of S+, 31P+. 75As+ and Se+........................................ 336
5.5 Elemental ions behavior with C2H4 as the reaction gas........................................ 344
5.5.1 Reaction rates between elemental ions and C2H4........................................... 344
5.5.2 Identification of product ions from reactions between elemental ions and
C2H4.......................................................................................................................... 351
5.6 Conclusions........................................................................................................... 358
6. Simulation of sample and blank signals as a function of relative reaction rates, gas
flow rate, overlap ion signal and contamination........................................................ 363
6.1 Introduction........................................................................................................... 363
6.2 Experimental......................................................................................................... 366
6.3 Discussion............................................................................................................. 374
6.3.1 Simulated CGOs vs experimentally measured data........................................ 374
6.3.2 Reaction rates and BEC vs EDL..................................................................... 385
6.4 Conclusions........................................................................................................... 395
7. Strategies to develop methods using ion-molecule reactions in a quadrupole
reaction cell to overcome spectral overlaps in inductively coupled plasma mass
spectrometry............................................................................................................... 399
7.1 Abstract................................................................................................................. 399
7.2 Introduction........................................................................................................... 400
7.3 Experimental......................................................................................................... 408
7.4 Results and Discussion.......................................................................................... 410
7.4.1 Removal of spectral overlap ion to measure analyte ion at its elemental
m/z........................................................................................................................... 410
7.4.1.1 Reaction with overlap ion......................................................................... 411
7.4.1.2 Assessment of analyte ion signal loss....................................................... 416
7.4.1.3 Assessment and prevention of new, undesired reaction product ions and
rejection at the analyte ion m/z............................................................................. 418
7.4.1.4 Product ions produced at higher masses................................................... 419
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7.4.1.5 Efficiency of prevention of new, undesired product ions......................... 420
7.4.1.6 Optimization of reaction gas flow rate and cell parameters...................... 423
7.4.2 Reaction to produce a new analyte-containing molecular ion at a higher
m/z............................................................................................................................ 427
7.4.2.1 Reaction of analyte with molecular gas to form new analyte-containing
product ion............................................................................................................ 428
7.4.2.2 Reaction of overlap ion with reaction gas................................................. 430
7.4.2.3 Other ions at the m/z of the analyte-containing product ion..................... 431
7.4.2.4 Assessment and prevention of new, undesired reaction product ions and
rejection at the analyte ion m/z............................................................................. 433
7.4.2.5 Optimization of reaction gas flow rate and cell parameters...................... 437
7.5 Conclusions........................................................................................................... 438
8. High precision isotope ratio measurements of nickel and iron with an inductively
coupled plasma dynamic reaction cel mass spectrometer (ICP-DRC-MS)............... 468
8.1 Purpose.................................................................................................................. 468
8.2 Introduction........................................................................................................... 468
8.3 Possion counting statistics.................................................................................... 472
8.4 Experimental......................................................................................................... 473
8.5 Results and discussion.......................................................................................... 476
8.5.1 Ion packet broadening..................................................................................... 476
8.5.2 Damping of plasma fluctuations in the ion beam............................................ 478
8.5.3 Dwell time vs %RSD...................................................................................... 479
8.5.4 Precision of Isotope ratio measurements........................................................ 481
8.6 Conclusions........................................................................................................... 485
Bibliography................................................................................................................... 489
Appendix A.................................................................................................................... 517
Appendix B.................................................................................................................... 520
Appendix C.................................................................................................................... 524