Preface xiii
1 General Concepts 1
1.1 Introduction 1
1.2 Migration and Retention 2
1.2.1 General 2
1.2.2 Mobile and Stationary Phases 3
1.2.3 Chromatograms 3
1.2.4 Retention Factor 3
1.3 Band Broadening 5
1.3.1 Eddy Diffusion 6
1.3.2 Longitudinal Diffusion 6
1.3.3 Resistance to Mass Transfer 7
1.3.4 Combined Band Broadening in a Column 8
1.3.5 Band Broadening outside the Column 9
1.4 Measuring Column Efficiency 9
1.4.1 Plate Numbers 9
1.4.2 Coupling Columns 10
1.4.3 Plate Height 10
1.4.3.1 Reduced Plate Height 11
1.4.4 Effective Plate Number 11
1.4.5 Asymmetry 11
1.5 Resolution 11
1.5.1 Increasing the Resolution 13
1.6 Peak Capacity 13
1.7 Two-Dimensional Systems 13
1.8 Increased Performance 14
References 15
2 Gas Chromatography 17
2.1 Introduction 17
2.2 Mobile Phase/Carrier Gas 17
2.3 Injection Systems 19
2.3.1 Packed Column Injector (Evaporation Injector) 20
2.3.2 Injection Systems for Capillary Columns 21
2.3.2.1 Split Injection 21
2.3.2.2 Splitless Injection 22
2.3.2.3 On-Column Injection 22
2.3.2.4 Large-Volume Injectors 23
2.3.2.5 Headspace Techniques 23
2.4 Columns 24
2.4.1 Packed Columns 25
2.4.2 Open Tubular Columns 25
2.5 Detectors 26
2.5.1 Introduction 26
2.5.2 Thermal Conductivity Detector 28
2.5.3 Flame Ionization Detector 28
2.5.4 Nitrogen–Phosphorus Detector 30
2.5.5 Electron Capture Detector 31
2.5.6 Mass Spectrometry 32
2.5.6.1 Positive Ionization 33
2.5.6.2 Negative Ionization 33
2.5.6.3 Gas Chromatography–Mass Spectrometry (GC–MS) Interfacing 33
2.5.7 Other Detectors 35
2.5.7.1 The Flame Photometric Detector 35
2.5.7.2 The Chemiluminescent Detector 35
2.5.7.3 The Electrolytic Conductivity Detector 35
2.5.7.4 The Photoionization Detector 35
2.5.7.5 The Atomic Emission Detector 36
2.5.7.6 Fourier Transform Infrared Detector 36
2.6 Stationary Phases 36
2.6.1 GSC – Adsorption Chromatography 36
2.6.2 GLC – Partition Chromatography 37
2.6.2.1 Matrix 37
2.6.2.2 Choosing the Stationary Phase 37
2.6.2.3 Types of Stationary Phases in GLC 38
2.6.2.4 Stationary Phase (Film) Thickness 40
2.6.2.5 Temperature 41
2.7 Two-Dimensional Separations 42
2.8 Qualitative and Quantitative Analyses 43
2.9 Derivatization 44
References 46
3 High-Performance Liquid Chromatography (HPLC) 47
3.1 Introduction 47
3.2 Solvents and Solvent Delivery 47
3.2.1 Maintenance 49
3.2.2 Automation 50
3.3 Injection 50
3.3.1 Techniques 50
3.3.1.1 Constant Volume Injection 50
3.3.1.2 Variable Volume Injection 51
3.3.1.3 Volumes and Precision 51
3.3.2 Dilution and Refocusing 51
3.3.2.1 Injection Volume Related to Solvent Elution Strength 51
3.3.2.2 Timed Injection 52
3.3.2.3 Carryover 52
3.3.2.4 Combination with Solid-Phase Extractors 52
3.3.3 Calculation of Maximum Injection Volumes 53
3.3.4 Calculating the Dilution of the Analyte in the Column 54
3.4 Columns 54
3.4.1 Packed Columns 54
3.4.1.1 Column Dimensions and Materials 54
3.4.1.2 Effect on Detection 55
3.4.1.3 Solvent Saving 55
3.4.1.4 Column Efficiency 56
3.4.1.5 Column Lifetime 57
3.4.1.6 Peak Shapes 57
3.4.1.7 Flow and Backpressure 58
3.4.1.8 Conventional Totally Porous Particles 58
3.4.1.9 Core–Shell Particles 58
3.4.1.10 Ultrahigh-Pressure LC (UHPLC or UPLC) 59
3.4.2 Monolithic Columns 59
3.4.3 Microchip Columns 60
3.4.4 Open Tubular Columns 61
3.4.5 Temperature Control 61
3.4.6 Preparative LC and Flash Chromatography 63
3.5 Stationary Phases and Their Properties in HPLC 64
3.5.1 Normal-Phase Materials for Adsorption Chromatography 64
3.5.1.1 Separation Principles 64
3.5.1.2 Silica 65
3.5.1.3 Alumina, Titania, and Zirconia 65
3.5.1.4 Silica with Bonded Polar Functional Groups 66
3.5.1.5 Hydrophilic Interaction Liquid Chromatography (HILIC) 67
3.5.1.6 Carbon Materials 68
3.5.2 Reversed-phase Materials 68
3.5.2.1 Separation Principles 68
3.5.2.2 Retention 69
3.5.2.3 The Solvation Parameter Model 70
3.5.2.4 Silica-based Reversed-phase Materials 71
3.5.2.5 Hybrid Materials and Hydrosilated Materials 72
3.5.2.6 Organic Polymer-based Materials 72
3.5.2.7 Ion Pair Chromatography on Reversed-Phase Columns 72
3.5.2.8 Hydrophobic Interaction Chromatography 73
3.5.3 Ion Exchange Materials 73
3.5.3.1 Elution 74
3.5.3.2 Retention 74
3.5.4 Chromatofocusing 74
3.5.4.1 Ion Chromatography for Inorganic Ions 75
3.5.5 Size Exclusion Materials 76
3.5.5.1 Separation Principles 76
3.5.5.2 Materials 76
3.5.5.3 Mobile Phases 77
3.5.6 Materials for Chiral Separations 77
3.5.6.1 Separation Principle 77
3.5.6.2 Materials 78
3.5.7 Affinity Materials 78
3.5.7.1 Separation Principle 78
3.5.7.2 Affinity Materials for Chromatography and Microarrays 79
3.6 Detectors 80
3.6.1 UV Detection 81
3.6.1.1 Some Common Chromophores 82
3.6.1.2 Choosing the Right Wavelength 82
3.6.1.3 Flow Cells 82
3.6.1.4 Filter Photometric Detection 83
3.6.1.5 Spectrophotometric Detection 83
3.6.1.6 Diode Array Detectors 83
3.6.2 Mass Spectrometric Detection 85
3.6.2.1 Electrospray Ionization 86
3.6.2.2 Atmospheric Pressure Chemical Ionization 88
3.6.2.3 Atmospheric Pressure Photoionization 89
3.6.2.4 Inductively Coupled Plasma Ionization 90
3.6.2.5 Mass Analysis 91
3.6.2.6 The Quadrupole Mass Analyzers 91
3.6.2.7 The Ion Trap Analyzers 92
3.6.2.8 The Time-of-Flight Analyzers 92
3.6.2.9 The FTMS Analyzers 93
3.6.2.10 Fragmentation in Mass Spectrometry 94
3.6.3 Fluorescence Detection 95
3.6.3.1 Filter Fluorimeters 97
3.6.3.2 Spectrofluorimeters 97
3.6.3.3 Chemiluminescence Detection 97
3.6.4 Electrochemical Detection 98
3.6.4.1 Amperometric Detection 98
3.6.4.2 Coulometric Detector 99
3.6.5 Light Scattering Detection 100
3.6.6 Refractive Index Detection 100
3.6.7 Other Detectors 102
3.6.7.1 The Conductivity Detector 102
3.6.7.2 The Corona Discharge Detector 102
3.6.7.3 Radioactivity Detectors 102
3.6.7.4 Ion Mobility Spectrometry 103
3.6.7.5 Chemiluminescent Nitrogen Detector 103
3.6.7.6 Chirality Detection 103
3.7 Increased Performance 103
3.7.1 Speed 103
3.7.2 Efficiency 103
3.7.3 Resolution 103
3.7.4 Detection 103
3.7.5 Column Lifetime 104
References 104
4 Thin Layer Chromatography (TLC) 105
4.1 Introduction 105
4.2 Sample Application 105
4.3 Stationary Phases 106
4.3.1 TLC versus HPTLC 106
4.3.2 Adsorbents 107
4.3.3 Chemically Bonded Phases 107
4.4 Mobile Phases 107
4.5 Elution and Development 108
4.5.1 Vertical Linear Development 108
4.5.2 Horizontal Development 109
4.5.3 Two-Dimensional Development 110
4.5.4 Gradient Development 111
4.5.5 Overpressured Layer Chromatography (OPLC) 111
4.6 Rf Value 111
4.7 Detection 112
4.7.1 Instrumental Detection 113
4.7.2 TLC–MS 114
5 Supercritical Fluid Chromatography 115
5.1 Introduction 115
5.2 Mobile Phases 118
5.2.1 CO2 as Mobile Phase 118
5.2.2 Mobile Phase Delivery 119
5.3 Gradient Elution 120
5.4 Injection 121
5.5 Columns 122
5.6 Restrictors 124
5.7 Detectors 124
5.8 Current Performance 125
References 126
6 Electrophoresis and Potential-Driven Chromatography 127
6.1 Introduction 127
6.2 Theory 127
6.2.1 Secondary Effects 128
6.2.2 Electroosmosis 129
6.3 Gel Electrophoresis Techniques 130
6.3.1 Gels 130
6.3.1.1 Polyacrylamide Gels 130
6.3.1.2 Agarose Gels 131
6.3.2 Instrumentation 131
6.3.2.1 Sample Application 131
6.3.2.2 Separation 132
6.3.2.3 Detection 132
6.3.3 Zone Electrophoresis 133
6.3.4 Isoelectric Focusing 134
6.3.5 Two-Dimensional Separations 134
6.3.6 Selected Applications 134
6.3.6.1 Protein Separations 134
6.3.6.2 Separation of DNA/RNA 135
6.4 Capillary Electrophoresis 135
6.4.1 Instrumentation 136
6.4.1.1 High-Voltage Supply 136
6.4.1.2 Capillaries 136
6.4.1.3 Sample Introduction 137
6.4.1.4 Detection 139
6.4.2 CE Zone Electrophoresis 140
6.4.3 Other CE Separation Principles 142
6.4.3.1 Isoelectric Focusing 142
6.4.3.2 Gel Electrophoresis in CE 142
6.4.3.3 Gel-Free Sieving 142
6.4.3.4 Isotachophoresis 143
6.4.4 Micellar Electrokinetic Capillary Chromatography (MEKC) 143
6.5 Potential-Driven Chromatography (Electrochromatography – CEC) 145
6.5.1 Instrumentation 145
6.5.2 Mobile Phases 145
6.5.3 Columns and Stationary Phases 146
6.5.4 CEC in Separation Science 146
References 147
7 Chromatography on a Chip 149
7.1 Introduction 149
7.2 Sample Introduction 149
7.3 Columns and Stationary Phases 151
7.3.1 Open Channel Columns 152
7.3.2 Packed Columns 152
7.3.3 Monolithic Columns 152
7.3.4 COMOSS 152
7.4 Flow Management 152
7.5 Detection 153
Reference 154
8 Field-Flow Fractionation 155
8.1 Introduction 155
8.2 Types of FFF 156
8.2.1 Flow FFF 156
8.2.2 Thermal FFF 157
8.2.3 Sedimentation FFF 158
8.3 Applications 158
Reference 159
9 Sample Preparation 161
9.1 Introduction 161
9.1.1 Recovery 162
9.1.2 Enrichment 162
9.2 Liquid–Liquid Extraction 164
9.2.1 Back Extraction 167
9.3 Solid-Phase Extraction (SPE) 168
9.3.1 Normal Phase 170
9.3.2 Reversed Phase 172
9.3.3 Ion Exchange 172
9.3.4 Mixed-Mode Ion Exchange 175
9.3.5 MIP 175
9.3.6 RAM 176
9.3.7 SPE Hardware 176
9.3.7.1 Disks 177
9.4 SPME 178
9.4.1 Adsorption/Extraction 178
9.4.2 Desorption/Injection 179
9.4.2.1 SPME–GC 180
9.4.2.2 SPME–HPLC 180
9.4.3 SPME Fiber Materials and Extraction Parameters 180
9.4.3.1 pH 181
9.4.3.2 Ionic Strength 181
9.4.3.3 Water and Organic Solvents 181
9.4.3.4 Temperature 181
9.4.3.5 Agitation 181
9.4.3.6 Extraction Time 182
9.5 Protein Precipitation 182
9.6 Membrane-Based Sample Preparation Techniques 183
9.6.1 Microdialysis 183
9.6.1.1 Perfusion Flow Rate 184
9.6.1.2 Diameter and Length 184
9.6.1.3 Cutoff 184
9.6.1.4 Membrane Chemistry 184
9.6.1.5 Application of Microdialysis 185
9.6.1.6 How to Analyze the Dialysate? 185
9.6.2 LPME 185
9.6.2.1 Two-Phase LPME 186
9.6.2.2 Three-Phase LPME 186
9.6.2.3 Enrichment in LPME 186
9.6.2.4 Donor Phase pH 187
9.6.2.5 Acceptor Phase pH 187
9.6.2.6 Composition of the SLM 187
9.6.2.7 Extraction Time 188
References 188
10 Quantitation 189
10.1 Introduction 189
10.2 Calibration Methods 192
10.2.1 External Standard 192
10.2.2 Internal Standard 193
10.2.3 Standard Addition 194
10.3 Method Validation 196
10.3.1 Validation Parameters 196
10.3.1.1 Linearity and Range 197
10.3.1.2 Repeatability 197
10.3.1.3 Accuracy 197
10.3.1.4 Selectivity 197
10.3.1.5 Robustness 197
10.3.1.6 Stability 198
10.3.2 Validation Procedure: A Simple Example 198
Reference 199
Index 201
