Principles and Practice of Modern Chromatographic Methods

509 Pages·1995·15.492 MB·English

by  Kevin Robards, P. E. Jackson, Paul R. Haddad

Principles and Practice of
Modern Chromatographic
Methods
This page intentionally left blank
Principles and Practice
of Modern
Ch romatog ra ph ic
Methods
K. Robards
School of Science and Technology
Charles Sturt University, Wagga Wagga
Australia
P. R. Haddad
Department of Chemistry
University of Tasmania, Hobart
Australia
P. E. Jackson
Waters Chromatography
Lane Cove
Australia
ELSEVIER
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First edition printed 1994
Reprinted2004
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Contents
Preface xi
1. Introduction and Overview 1
1.1 Introduction 2
1.2 Historical Aspects 3
1.3 Chromatographic Separation Simply Explained 8
1.4 Classification of Chromatography 9
1.4.1 Mobile phase 10
1.4.2 Technique 10
1.4.3 Development mode 15
1.4.4 Separation mechanism 16
1.4.5 Other systems of classification 23
1.5 Information and Objectives of Chromatography 23
1.5.1 Qualitative applications 24
1.5.2 Quantitative applications 25
1.5.3 Preparative applications 25
1.6 Comparison of Chromatographic Techniques 25
1.7 Obtaining Assistance 29
References 30
Bibliography 32
2. Theory of Chromatography 35
2.1 Introduction 36
2.2 Chromatographic Retention 36
2.2.1 Parameters for column techniques 37
2.2.2 Parameters for planar techniques 44
2.3 Peak Shape 45
2.4 Zone Broadening and Measures of Efficiency 49
2.4.1 Plate theory 49
2.4.2 Rate theory 53
2.4.3 Van Deemter plot 57
2.4.4 Extra-column effects in zone broadening 58
2.4.5 Other measures of separation efficiency 61
2.5 Optimizing Resolution 64
2.5.1 Maximizing resolution by optimizing partition ratio 66
2.5.2 Maximizing resolution by optimizing column efficiency 68
2.5.3 Maximizing resolution by optimizing column selectivity 68
2.6 Overall System Performance 71
vi Contents
References 71
Bibliography 73
3. Gas Chromatography 75
3.1 Introduction 76
3.1.1 Organization of this chapter 77
3.1.2 Sample type 77
3.2 Mobile Phases 78
3.2.1 Carrier gas purification-oxygen and moisture traps 80
3.2.2 Carrier gas regulation 81
3.3 Systems for Sample Introduction 82
3.3.1 Syringes 83
3.3.2 Septa 86
3.3.3 Sample inlet systems 87
3.4 Columns 95
3.4.1 Column materials 98
3.4.2 Column activity 99
3.4.3 Open tubular columns 101
3.5 Column Packing Materials 109
3.5.1 Gas-solid chromatography 111
3.5.2 Gas-liquid chromatography 114
3.6 Column Temperature 131
3.6.1 Temperature programming 132
3.7 Detectors 133
3.7.1 Detector specifications 134
3.7.2 Make-up gas 135
3.7.3 Common detectors used in gas chromatography 135
3.7.4 Dual detection 142
3.8 System Evaluation 143
3.8.1 Test solutions 143
3.8.2 Performance tests 145
3.9 Ancillary Techniques 148
3.9.1 Derivatization 149
3.9.2 Pyrolysis gas chromatography 154
3.9.3 Headspace gas chromatography 154
3.9.4 Multidimensional gas chromatography 156
3.9.5 High-speed gas chromatography 157
3.9.6 Coupled techniques 159
References 170
Bibliography 174
4. Planar Chromatography 179
4.1 Introduction 180
4.1.1 Paper chromatography 180
4.1.2 Thin layer chromatography 182
4.2 Why Thin Layer Chromatography? 182
4.2.1 Comparison of conventional TLC and HPTLC 183
4.2.2 Comparison of TLC with other techniques 184
Contents vii
4.3 Theoretical Considerations 186
4.3.1 Forced flow conditions 189
4.4 Thin Layer Plates 190
4.5 Stationary Phases 192
4.5.1 Polar inorganic materials 193
4.5.2 Non-polar inorganic materials 196
4.5.3 Non-polar bonded phases 196
4.5.4 Polar bonded phases 197
4.5.5 Other phases 198
4.5.6 Activity 198
4.6 Mobile Phases 202
4.6.1 Mobile phase optimization 202
4.7 Sample Application 208
4.8 Development Techniques 210
4.8.1 Linear development 210
4.8.2 Circular and anticircular development 210
4.8.3 Continuous and multiple development 211
4.8.4 Development chambers 213
4.8.5 Forced flow 215
4.9 Detection 216
4.9.1 Direct examination 216
4.9.2 Spray reagents 216
4.9.3 Miscellaneous 217
4.9.4 Qualitative analysis 218
4.10 Quantification 218
4.10.1 Elution techniques 218
4.10.2 In situ visual evaluation 219
4.10.3 In situ optical scanners 219
4.10.4 Other measuring systems 223
References 224
Bibliography 225
5. High-performance Liquid Chromatography-Instrumentation and Techniques 227
5.1 Introduction 228
5.2 Solvent Delivery Systems 229
5.2.1 General requirements 229
5.2.2 Materials of construction 230
5.2.3 Mobile phase reservoirs 231
5.2.4 Reciprocating HPLC pumps 232
5.2.5 Other types of HPLC pump 236
5.3 Sample Introduction in HPLC 236
5.3.1 Manual injection 237
5.3.2 Automated injection 240
5.4 Column Packings and Hardware 241
5.4.1 Introduction 241
5.4.2 Column packings 241
5.4.3 Column packing methods 243
viii Contents
5.4.4 Column configuration and hardware 245
5.4.5 Measuring column performance 246
5.4.6 Column care and use 248
5.5 Detectors 249
5.5.1 Introduction 249
5.5.2 U.v.-visible light absorbance detectors 251
5.5.3 Fluorescence detectors 257
5.5.4 Electrochemical detection 260
5.5.5 Refractive index detectors 269
5.5.6 Conductivity detectors 272
5.5.7 Comparison of detectors 277
5.6 Gradient Elution 277
5.6.1 Introduction 277
5.6.2 Equipment for gradient elution 278
5.6.3 Gradient optimization 281
5.6.4 Gradient applications and considerations 284
5.7 Derivatization Methods 285
5.7.1 Introduction 285
5.7.2 Hardware and procedures for pre-column derivatization 287
5.7.3 Hardware and procedures for post-column derivatization 287
5.7.4 Applications of derivatization 292
5.8 Preparative Chromatography 292
5.8.1 Instrumentation for preparative chromatography 293
5.8.2 Preparative separations 293
5.8.3 Preparative applications 295
5.9 Multidimensional Liquid Chromatography 297
5.9.1 Column switching 297
5.9.2 Applications of coupled chromatography 298
References 300
Bibliography 301
6. High-performance Liquid Chromatography-Separations 305
6.1 Introduction 306
6.1.1 Chromatographic separations 306
6.1.2 Organization of this chapter 307
6.2 Separation of Neutral Compounds 308
6.2.1 Normal-phase chromatography 308
6.2.2 Reversed-phase chromatography 316
6.2.3 Gel permeation chromatography 333
6.3 Techniques for Ionic and Ionizable Species 341
6.3.1 Ion-suppression chromatography 342
6.3.2 Ion-interaction chromatography 344
6.3.3 Ion-exchange chromatography 351
6.3.4 Ion chromatography 358
6.3.5 Ion-exclusion chromatography 365
6.4 Speciality Separation Modes 370
6.4.1 Hydrophobic interaction chromatography 371
Contents IX
6.4.2 Affinity chromatography 371
6.4.3 Complexation chromatography 374
6.4.4 Chiral chromatography 375
6.5 Choosing a Chromatographic Method 378
References 378
Bibliography 379
7. Supercritical Fluid Chromatography 381
7.1 Introduction 382
7.2 Instrumentation 384
7.2.1 Mobile phase delivery system 385
7.2.2 Injection systems 386
7.2.3 Restrictors 388
7.2.4 Detectors 389
7.3 Columns 390
7.3.1 Open tubular columns 391
7.3.2 Packed columns 392
7.4 Factors Affecting Retention 394
7.4.1 Solubilizing power 394
7.4.2 Temperature/pressure effects on solute solubility and retention 396
7.5 Mobile Phases 398
7.5.1 Single component phases 399
7.5.2 Modifiers 400
7.6 Programming Techniques 402
7.7 Areas of Application 403
References 403
Bibliography 404
8. Sample Handling in Chromatography 407
8.1 Introduction 408
8.2 Sample Collection Procedures 409
8.2.1 Sampling of particulates, aerosols and gases 410
8.3 Sample Preparation-An Overview 412
8.4 Recovery Procedures 414
8.4.1 Solvent extraction 415
8.4.2 Supercritical fluid extraction 423
8.4.3 Volatilization processes 429
8.5 Sample Clean-up Methods 433
8.5.1 Membrane techniques 433
8.5.2 Chromatography 440
8.5.3 Solid phase extraction 445
8.5.4 Chemical modification of the sample by pre-column reaction 450
8.6 Preconcentration Techniques 450
8.7 Contamination Effects 452
References 452
Bibliography 454