Capillary Electrophoresis and Microchip Capillary Electrophoresis
Principles, Applications, and Limitations

Explores the benefits and limitations of the latest capillary electrophoresis techniques

Capillary electrophoresis and microchip capillary electrophoresis are powerful analytical tools that are particularly suited for separating and analyzing biomolecules. In comparison with traditional analytical techniques, capillary electrophoresis and microchip capillary electrophoresis offer the benefits of speed, small sample and solvent consumption, low cost, and the possibility of miniaturization.

With contributions from a team of leading analytical scientists, Capillary Electrophoresis and Microchip Capillary Electrophoresis explains how researchers can take full advantage of all the latest techniques, emphasizing applications in which capillary electrophoresis has proven superiority over other analytical approaches. The authors not only explore the benefits of each technique, but also the limitations, enabling readers to choose the most appropriate technique to analyze a particular sample.

The book's twenty-one chapters explore fundamental aspects of electrophoretically driven separations, instrumentation, sampling techniques, separation modes, detection systems, optimization strategies for method development, and applications. Specific topics include:

• Critical evaluation of the use of surfactants in capillary electrophoresis
• Sampling and quantitative analysis in capillary electrophoresis
• Capillary electrophoresis with electrochemical detection
• Overcoming challenges in using microchip electrophoresis for extended monitoring applications
• Capillary electrophoresis of intact unfractionated heparin and related impurities
• Microchip capillary electrophoresis for in situ planetary exploration

Each chapter begins with an introduction and ends with conclusions as well as references to the primary literature. Novices to the field will find this book an easy-to-follow introduction to core capillary electrophoresis techniques and methods. More experienced investigators can turn to the book for troubleshooting tips and expert advice to guide them through the most advanced applications.

PREFACE xvii

ACKNOWLEDGMENTS xix

CONTRIBUTORS xxi

1 Critical Evaluation of the Use of Surfactants in Capillary Electrophoresis 1
Jessica L. Felhofer, Karin Y. Chumbimuni-Torres, Maria F. Mora, Gabrielle G. Haby, and Carlos D. Garcý´a

1.1 Introduction 1

1.2 Surfactants for Wall Coatings 4

1.2.1 Controlling the Electroosmotic Flow 4

1.2.2 Preventing Adsorption to the Capillary 5

1.3 Surfactants as Buffer Additives 6

1.3.1 Micellar Electrokinetic Chromatography 6

1.3.2 Microemulsion Electrokinetic Chromatography 8

1.3.3 Nonaqueous Capillary Electrophoresis with Added Surfactants 9

1.4 Surfactants for Analyte Preconcentration 9

1.4.1 Sweeping 10

1.4.2 Transient Trapping 11

1.4.3 Analyte Focusing by Micelle Collapse 12

1.4.4 Micelle to Solvent Stacking 12

1.4.5 Combinations of Preconcentration Methods 12

1.4.6 Cloud Point Extraction 12

1.5 Surfactants and Detection in CE 14

1.5.1 Mass Spectrometry 14

1.5.2 Electrochemical Detection 15

1.6 Conclusions 16

References 17

2 Sample Stacking: A Versatile Approach for Analyte Enrichment in CE and Microchip-CE 23
Bruno Perlatti, Emanuel Carrilho, and Fernando Armani Aguiar

2.1 Introduction 23

2.2 Isotachophoresis 24

2.3 Chromatography-Based Sample Stacking 25

2.4 Methods Based on Electrophoretic Mobility and Velocity Manipulation (Electrophoretic Methods) 26

2.4.1 Field-Enhanced Sample Stacking (FESS) 27

2.4.2 Field-Enhanced Sample Injection (FESI) 27

2.4.3 Large-Volume Sample Stacking (LVSS) 28

2.4.4 Dynamic pH Junction 28

2.5 Sample Stacking in Pseudo-Stationary Phases 29

2.5.1 Field-Enhanced Sample Stacking 29

2.5.2 Hydrodynamic Injection Techniques 30

2.5.2.1 Normal Stacking Mode (NSM) 30

2.5.2.2 Reverse Electrode Polarity Stacking Mode (REPSM) 30

2.5.2.3 Stacking with Reverse Migrating Micelles (SRMM) 30

2.5.2.4 Stacking Using Reverse Migrating Micelles and a Water Plug (SRW) 31

2.5.2.5 High-Conductivity Sample Stacking (HCSS) 31

2.5.3 Electrokinetic Injection Techniques 32

2.5.3.1 Field-Enhanced Sample Injection (FESI–MEKC) 32

2.5.3.2 Field-Enhanced Sample Injection with Reverse Migrating Micelles (FESI–RMM) 32

2.5.4 Sweeping 32

2.5.5 Combined Techniques 33

2.5.5.1 Dynamic pH Junction: Sweeping 33

2.5.5.2 Selective Exhaustive Injection (SEI) 33

2.5.6 New Techniques 33

2.6 Stacking Techniques in Microchips 33

2.7 Concluding Remarks 36

References 37

3 Sampling and Quantitative Analysis in Capillary Electrophoresis 41
Petr Kuba´9n, Andrus Seiman, and Mihkel Kaljurand

3.1 Introduction 41

3.2 Injection Techniques in CE 42

3.2.1 Hydrodynamic Sample Injection 43

3.2.1.1 Principle 43

3.2.1.2 Advantages and Performance 44

3.2.1.3 Disadvantages 44

3.2.2 Electrokinetic Sample Injection 44

3.2.2.1 Principle 44

3.2.2.2 Advantages and Performance 45

3.2.2.3 Disadvantages 45

3.2.3 Bias-Free Electrokinetic Injection 45

3.2.4 Extraneous Sample Introduction Accompanying Injections in CE 46

3.2.5 Sample Stacking 48

3.2.5.1 Principle 48

3.2.5.2 Advantages and Performance 49

3.2.5.3 Disadvantages 50

3.2.6 Alternative Batch Sample Injection Techniques 50

3.2.6.1 Rotary-Type Injectors for CE 50

3.2.6.2 Hydrodynamic Sample Splitting as Injection Method for CE 51

3.2.6.3 Electrokinetic Sample Splitting as Injection Method for CE 52

3.2.6.4 Dual-Opposite End Injection in CE 52

3.3 Micromachined/Microchip Injection Devices 53

3.3.1 Droplet Sampler Based on Digital Microfluidics 53

3.3.2 Wire Loop Injection 54

3.4 Automated Flow Sample Injection and Hyphenated Systems 55

3.4.1 Introduction 55

3.4.2 Advantages and Performance 56

3.4.3 Disadvantages 57

3.5 Computerized Sampling and Data Analysis 57

3.6 Sampling in Portable CE Instrumentation 58

3.7 Quantitative Analysis in CE 59

3.7.1 Introduction 59

3.7.2 Quantitative Analysis with HD Injection 59

3.7.3 Quantitative Analysis with EK Injection 60

3.7.4 Validation of the Developed CE Methods 61

3.7.5 Computer Data Treatment in Quantitative Analysis 61

3.8 Conclusions 62

References 62

4 Practical Considerations for the Design and Implementation of High-Voltage Power Supplies for Capillary and Microchip Capillary Electrophoresis 67
Lucas Blanes, Wendell Karlos Tomazelli Coltro, Renata Mayumi Saito, Claudimir Lucio do Lago, Claude Roux, and Philip Doble

4.1 Introduction 67

4.1.1 High-Voltage Fundamentals 67

4.1.2 Electroosmotic Flow Control 68

4.1.3 Technical Aspects 70

4.1.4 Construction of Bipolar HVPS from Unipolar HVPS 70

4.1.5 Safety Considerations 71

4.1.6 HVPS Commercially Available 71

4.1.7 Practical Considerations 72

4.1.8 Alternative Sources of HV 72

4.1.9 HVPS Controllers for MCE 72

4.2 High-Voltage Measurement 73

4.3 Concluding Remarks 74

References 74

5 Artificial Neural Networks in Capillary Electrophoresis 77
Josef Havel, Eladia Marýa Pe~na-Mendez, and Alberto Rojas-Hernandez

5.1 Introduction 77

5.2 Optimization in CE: From Single Variable Approach Toward Artificial Neural Networks 77

5.2.1 Limitations of “Traditional” Single Variable Approach 79

5.2.2 Multivariate Approach with Experimental Design and Response Surface Modeling 79

5.2.2.1 Experimental Design 79

5.2.2.2 Response Surface Modeling 80

5.3 Artificial Neural Networks in Electromigration Methods 81

5.3.1 Introduction—Basic Principles of ANN 81

5.3.2 Optimization Using a Combination of ED and ANN 82

5.3.2.1 Testing of ED–ANN Algorithm 83

5.3.2.2 Practical Applications of ED–ANN 83

5.3.3 Quantitative CE Analysis and Determination from Overlapped Peaks 84

5.3.3.1 Evaluation of Calibration Plots in CE Using ANN to Increase Precision of Analysis 84

5.3.3.2 ANN in Quantitative CE Analysis from Overlapped Peaks 86

5.3.4 ANN in CEC and MEKC 86

5.3.5 ANN for Peptides Modeling 88

5.3.6 Classification and Fingerprinting 88

5.3.7 Other Applications 90

5.4 Conclusions 90

Acknowledgments 91

References 91

6 Improving the Separation in Microchip Electrophoresis by Surface Modification 95
M. Teresa Fernandez-Abedul, Isabel Alvarez-Martos, Francisco Javier Garcýa Alonso, and Agustýn Costa-Garcýa

6.1 Introduction 95

6.2 Strategies for Improving Separation 96

6.2.1 Selection of an Adequate Technique: ME 96

6.2.2 Microchannel Design 96

6.2.3 Selection of an Appropriate ME Material 96

6.2.4 Optimization of the Working Conditions 97

6.2.5 Surface Modification 97

6.2.5.1 Surface Micro- and Nanostructuring 98

6.2.5.2 Employment of Energy Sources 99

6.2.5.3 Chemical Surface Modification 99

6.3 Chemical Modifiers 102

6.3.1 Surfactants 104

6.3.2 Ionic Liquids 105

6.3.3 Nanoparticles 108

6.3.4 Polymers 110

6.4 Conclusions 119

Acknowledgments 120

References 120

7 Capillary Electrophoretic Reactor and Microchip Capillary Electrophoretic Reactor: Dissociation Kinetic Analysis Method for “Complexes” Using Capillary Electrophoretic Separation Process 127
Toru Takahashi and Nobuhiko Iki

7.1 Introduction 127

7.2 Basic Concept of CER 128

7.3 Dissociation Kinetic Analysis of Metal Complexes Using a CER 129

7.3.1 Determination of the Rate Constants of Dissociation of 1:2 Complexes of Al3þ and Ga3þ with an Azo Dye Ligand 2,20-Dihydroxyazobenzene-5,50-Disulfonate in a CER 130

7.4 Expanding the Scope of the CER to Measurements of Fast Dissociation Kinetics with a Half-Life from Seconds to Dozens of Seconds: Dissociation Kinetic Analysis of Metal Complexes Using a Microchip Capillary Electrophoretic Reactor (mCER) 133

7.5 Expanding the Scope of the CER to the Measurement of Slow Dissociation Kinetics with a Half-Life of Hours 135

7.5.1 Principle of LS-CER 135

7.5.2 Application of LS-CER to the Ti(IV)–Catechin Complex 136

7.5.3 Application of LS-CER to the Ti(IV)–Tiron Complex 138

7.6 Expanding the Scope of CER to Measurement of the Dissociation Kinetics of Biomolecular Complexes 139

7.6.1 Dissociation Kinetic Analysis of [SSB–ssDNA] Using CER 139

7.7 Conclusions 142

References 142

8 Capacitively Coupled Contactless Conductivity Detection (C4D) Applied to Capillary Electrophoresis (CE) and Microchip Electrophoresis (MCE) 145
Jose Alberto Fracassi da Silva, Claudimir Lucio do Lago, Dosil Pereira de Jesus, and Wendell Karlos Tomazelli Coltro

8.1 Introduction 145

8.2 Theory of C4D 145

8.2.1 Basic Principles of C4D 145

8.2.2 Simulation 146

8.2.3 Basic Equation for Sensitivity 147

8.2.4 Equivalent Circuit of a CE-C4D System 147

8.2.5 Practical Guidelines 148

8.3 C4D Applied to Capillary Electrophoresis 148

8.3.1 Instrumental Aspects in CE 149

8.3.2 Coupling C4D with UV–Vis Photometric Detectors in CE 149

8.3.3 Fundamental Studies in Capillary Electrophoresis Using C4D 149

8.3.4 Fundamental Studies on C4D 149

8.3.5 Applications 150

8.4 C4D Applied to Microchip Capillary Electrophoresis 151

8.4.1 Geometry of the Detection Electrodes 151

8.4.1.1 Embedded Electrodes 151

8.4.1.2 Attached Electrodes 153

8.4.1.3 External Electrodes 153

8.4.2 Applications 154

8.4.2.1 Bioanalytical Applications 154

8.4.2.2 On-Chip Enzymatic Reactions 155

8.4.2.3 Food Analysis 155

8.4.2.4 Explosives and Chemical Warfare Agents 155

8.4.2.5 Other Applications 156

8.5 Concluding Remarks 156

Acknowledgments 157

References 157

9 Capillary Electrophoresis with Electrochemical Detection 161
Blanaid White

9.1 Principles of Electrochemical Detection 161

9.1.1 Amperometric Detection 161

9.1.2 Potentiometric Detection 162

9.1.3 Conductivity Detection 162

9.2 Interfacing Amperometric Detection to Capillary Electrophoresis 163

9.2.1 Off-Column Detection 163

9.2.2 End-Column Detection 164

9.2.3 Use of Multiple Detection Electrodes 165

9.2.4 Pulsed Amperometric Detection 166

9.2.5 Nonaqueous EC Detection 166

9.2.6 Electrode Material 166

9.2.7 Dual Conductivity and Amperometric Detection 167

9.3 Interfacing Electrochemical Detection to Microfluidic Capillary Electrophoresis 168

9.3.1 End-Column Detection 168

9.3.2 Pulsed Amperometric Detection 169

9.3.3 Off-Channel Detection 169

9.3.4 Electrode Material 170

9.3.5 Portable CE and MCE Systems 170

9.3.6 Applications of CE–MCE with AD 171

9.3.7 Future Directions for CE–MCE with EC Detection 173

References 173

10 Overcoming Challenges in Using Microchip Electrophoresis for Extended Monitoring Applications 177
Scott D. Noblitt and Charles S. Henry

10.1 Introduction 177

10.2 Background Electrolyte (BGE) Longevity 179

10.3 Achieving Rapid Sequential Injections 186

10.4 Robust Quantitation 192

10.5 Conclusions 197

References 198

11 Distinction of Coexisting Protein Conformations by Capillary Electrophoresis 201
Hanno Stutz

11.1 Introduction 201

11.1.1 Theoretical Aspects of in vivo Protein Folding 202

11.2 Protein Misfolding and Induction of Unfolding 203

11.3 Conformational Pathologies 204

11.4 Distinction Between Conformations 205

11.5 Relevance of Conformations for Biotechnological Products 206

11.6 Conformational Elucidation—An Overview of Alternative Methods to CE 206

11.7 HPLC in Conformational Distinction 207

11.7.1 Intact Proteins 207

11.7.1.1 Reversed-Phase (RP)–HPLC 207

11.7.1.2 Size Exclusion (SEC)–HPLC 208

11.7.1.3 Ion-Exchange–HPLC 208

11.7.2 HPLC with Detectors Sensitive for Conformations and Aggregates 208

11.7.3 Peptides as Model Compounds for Hydrophobic Stationary Phases in HPLC 208

11.8 Capillary Electrophoresis (CE) in Conformational Separations 209

11.8.1 Fundamental Aspects and Survey of Pitfalls 209

11.8.2 Electrophoretic Mobility of Proteins 210

11.8.3 Peak Profiles and Derivable Thermodynamic Aspects of Protein Re-/Unfolding 211

11.8.4 Dipeptides as a Case Study for Isomerization 213

11.8.5 Denaturation Factors and Strategies Applied in CE 214

11.8.5.1 Separation Electrolyte, Injection Solution, and Sample Storage 215

11.8.5.2 Denaturation by Urea, Dithiothreitol, and GdmCl 215

11.8.5.3 Effects of pH and Organic Solvents 216

11.8.5.4 Temperature 216

11.8.5.5 Electrical Field 218

11.8.5.6 Detergents 218

11.8.5.7 Ligands and Ions—Case Studies on Potential Amyloidogenic b2m 221

11.8.6 b-Amyloid Peptides 222

11.8.6.1 Prions 223

11.9 Comparison Between CE and HPLC 223

11.10 Conclusive Discussion and Method Evaluation 223

11.10.1 General Aspects 223

11.10.2 HPLC 224

11.10.3 CE 224

References 225

12 Capillary Electromigration Techniques for the Analysis of Drugs and Metabolites in Biological Matrices: A Critical Appraisal 229
Cristiane Masetto de Gaitani, Anderson Rodrigo Moraes de Oliveira, and Pierina Sueli Bonato

12.1 Introduction 229

12.2 Strategies to Obtain Reliable Capillary Electromigration Methods for the Bioanalysis of Drugs and Metabolites 230

12.2.1 Selectivity and Detectability 230

12.2.1.1 Efficiency 232

12.2.1.2 Sample Preparation 233

12.2.1.3 Detectors 235

12.2.2 Repeatability 236

12.3 Selected Applications of Capillary Electromigration Techniques in Bioanalysis 238

12.3.1 Pharmacokinetics and Metabolism Studies 238

12.3.2 Enantioselective Analysis of Drugs and Metabolites 240

12.3.3 Biopharmaceuticals or Biotechnology-Derived Pharmaceuticals 240

12.3.4 Therapeutic Drug Monitoring 241

12.3.5 Clinical and Forensic Toxicology 242

12.4 Concluding Remarks 243

References 243

13 Capillary Electrophoresis and Multicolor Fluorescent DNA Analysis in an Optofluidic Chip 247
Chaitanya Dongre, Hugo J.W.M. Hoekstra, and Markus Pollnau

13.1 Introduction 247

13.2 Optofluidic Integration in an Electrophoretic Microchip 248

13.2.1 Sample Fabrication 248

13.2.2 Optofluidic Characterization 248

13.3 Fluorescence Monitoring of On-Chip DNA Separation 249

13.3.1 Experimental Materials and Methods 249

13.3.2 Experimental Results and Analysis 250

13.4 Toward Ultrasensitive Fluorescence Detection 253

13.4.1 Optimization of the Experimental Setup 253

13.4.2 All-Numerical Postprocessed Noise Filtering 253

13.5 Multicolor Fluorescent DNA Analysis 255

13.5.1 Dual-Point, Dual-Wavelength Fluorescence Monitoring 256

13.5.2 Modulation-Frequency Encoded Multiwavelength Fluorescence Sensing 259

13.5.3 Application to Multiplex Ligation-Dependent Probe Amplification 260

13.6 Conclusions and Outlook 263

Acknowledgments 264

References 264

14 Capillary Electrophoresis of Intact Unfractionated Heparin and Related Impurities 267
Robert Weinberger

14.1 Introduction 267

14.2 Capillary Electrophoresis and Heparin 269

14.3 Method Development in Capillary Electrophoresis 269

14.4 Common Impurities Found in Heparin 272

14.5 The United States Pharmacoepia and CE of Heparin 273

14.6 Interlaboratory Collaborative Study 274

14.7 Conclusions 275

References 275

15 Microchip Capillary Electrophoresis for In Situ Planetary Exploration 277
Peter A. Willis and Amanda M. Stockton

15.1 Introduction 277

15.2 Instrument Design 279

15.3 Instrumentation External to the Microdevice 280

15.4 Microdevice Basics 282

15.4.1 All-Glass Devices for Microchip Capillary Electrophoresis 282

15.4.2 Three-Layer Hybrid Substrate Glass–PDMS Devices for Fluidic Manipulation 284

15.4.3 Integrating Fluidic Manipulation with Electrophoresis 285

15.5 Microdevices and their Applications 285

15.5.1 Microdevices with Bus-Valve Control of Microfluidic Manipulation 285

15.5.2 Automaton Devices for Programmable Microfluidic Manipulation 288

15.6 Conclusions 289

Acknowledgments 290

References 290

16 Rapid Analysis of Charge Heterogeneity of Monoclonal Antibodies by Capillary Zone Electrophoresis and Imaged Capillary Isoelectric Focusing 293
Yan He, Jim Mo, Xiaoping He, and Margaret Ruesch

16.1 Introduction 293

16.2 Capillary Zone Electrophoresis 295

16.2.1 Separation and Detection Strategy 295

16.2.1.1 Capillary Construction 295

16.2.1.2 Buffer Composition 295

16.2.1.3 Separation Voltage and Field Strength 297

16.2.1.4 Detection 297

16.2.2 Applications 297

16.3 Imaged Capillary Isoelectric Focusing 299

16.3.1 Method Development and Optimization 299

16.3.1.1 Carrier Ampholyte 300

16.3.1.2 Additives 300

16.3.1.3 Focusing Time and Voltage 300

16.3.1.4 Salt Concentration 303

16.3.1.5 Protein Concentration 303

16.3.2 iCE Method Validation 303

16.3.3 Applications 304

16.3.3.1 Cell Line Development Support 304

16.3.3.2 Formulation Screening 304

16.3.3.3 Characterization of Acidic Species 305

16.4 Summary 306

References 307

17 Application of Capillary Electrophoresis for High-Throughput Screening of Drug Metabolism 309
Roman 9Remý´nek, Jochen Pauwels, Xu Wang, Jos Hoogmartens, Zden9ek Glatz, and Ann Van Schepdael

17.1 Introduction 309

17.2 Sample Deproteinization 310

17.3 On-line Preconcentration 311

17.4 Method Development 312

17.4.1 Dynamic Coating of Inner Capillary Wall 312

17.4.2 Short-End Injection 313

17.4.3 Strong Rinsing Procedure 313

17.4.4 Optimized Method 313

17.5 Method Validation 314

17.6 Method Applications 315

17.6.1 Drug Stability Screening 315

17.6.2 Kinetic Study 316

17.7 Conclusions 316

Acknowledgments 317

References 317

18 Electrokinetic Transport of Microparticles in the Microfluidic Enclosure Domain 319
Qian Liang, Chun Yang, and Jianmin Miao

18.1 Introduction 319

18.2 Numerical Model 320

18.2.1 Problem Description 320

18.2.2 Mathematical Model 320

18.3 Numerical Simulation 322

18.4 Results and Discussion 322

18.4.1 Particle Transport in the Bulk Flow 322

18.4.1.1 The Particle Velocity in the Confined Domain 322

18.4.1.2 The Trajectory of Particle Transport within the Confined Domain 323

18.4.1.3 The Effect of Sidewall Zeta Potential on the Particle Motion 324

18.4.2 Particle Transport Near the Bottom Surface 325

18.4.2.1 The Effect of the EDLThickness on the Near Wall Motion of the Particle 325

18.4.2.2 The Effect of Surface Charge on the Near Wall Transport of the Particle 325

18.5 Model Application 325

18.6 Conclusions 326

References 326

19 Integration of Nanomaterials in Capillary and Microchip Electrophoresis as a Flexible Tool 327
Germa´n A. Messina, Roberto A. Olsina, and Patricia W. Stege

19.1 Introduction 327

19.1.1 Historical Overview of Nanotechnology 327

19.1.2 Nanomaterials 329

19.1.2.1 Carbon-Based Nanomaterials 329

19.1.2.2 Metal-Based Nanomaterials 329

19.1.2.3 Dendrimers 331

19.1.2.4 Composites 331

19.2 Nanomaterials in Analytical Chemistry 332

19.3 Nanoparticles in Capillary Electrophoresis 333

19.3.1 Nanoparticles in Capillary Electrochromatography 334

19.3.1.1 Organic Nanoparticles 334

19.3.1.2 Inorganic Particles 338

19.3.2 Nanoparticles in Electrokinetic Chromatography 342

19.3.2.1 Organic Nanoparticles 343

19.3.2.2 Inorganic Particles 347

19.3.3 Nanoparticles in Microchip Electrochromatography 349

19.4 Conclusions 352

References 353

20 Microchip Capillary Electrophoresis to Study the Binding of Ligands to Teicoplanin Derivatized on Magnetic Beads 359
Toni Ann Riveros, Roger Lo, Xiaojun Liu, Marisol Salgado, Hector Carmona, and Frank A. Gomez

20.1 Introduction 359

20.2 Experimental Section 359

20.2.1 Materials and Methods 359

20.2.1.1 Equipment and Fabrication of the Microchips 360

20.2.1.2 Surface Coating 360

20.2.1.3 Teic Immobilization on Magnetic Microbeads 360

20.2.2 Procedures 360

20.2.2.1 FAMCE Studies 360

20.2.2.2 MFAC Studies 361

20.3 Results and Discussion 361

20.3.1 FAMCE Studies 361

20.3.1.1 Nonspecific Adsorption Resistance 361

20.3.1.2 The Binding of DA3 to Teic-Beads 362

20.3.2 MFAC Studies 363

20.4 Conclusions 364

Acknowledgments 365

References 365

21 Glycomic Profiling Through Capillary Electrophoresis and Microchip Capillary Electrophoresis 367
Yehia Mechref

21.1 Introduction 367

21.1.1 Release of N-Glycans from Glycoproteins 368

21.1.1.1 Chemical Release 368

21.1.1.2 Enzymatic Release 368

21.1.2 Release of O-Glycans from Glycoproteins 368

21.1.2.1 Chemical Release 368

21.1.2.2 Enzymatic Release 369

21.2 General Considerations of Capillary Electrophoresis and Microchip Capillary Electrophoresis of Glycans 369

21.2.1 Capillary Electrophoresis–Laser-Induced Fluorescence (CE–LIF) Analysis of Glycans 369

21.2.2 Interfacing Capillary Electrophoresis and Capillary Electrochromatography to Mass Spectrometry 372

21.2.2.1 ESI Interfaces for Capillary Electrophoresis 372

21.2.2.2 Sheathless-Flow Interface 372

21.2.2.3 Sheath-Flow Interface 373

21.2.2.4 Liquid Junction Interface 373

21.2.2.5 MALDI Interfaces for Capillary Electrophoresis 373

21.2.2.6 CE–MS Analysis of Glycans 374

21.2.2.7 Glycomic Analysis by CEC–MS 376

21.3 Microchip Capillary Electrophoresis 377

21.4 Conclusions 380

References 381

INDEX 385

Carlos D. García, PhD, is an Associate Professor of Analytical Chemistry at the University of Texas at San Antonio, USA. His group is currently focused on the development of novel bioanalytical strategies involving microfluidics and nanomaterials.

Karin Y. Chumbimuni-Torres, PhD, is a Research Associate at the University of Texas at San Antonio, USA. She is interested in pursuing the development of electrochemical biosensors and their integration to microchip-based platforms.

Emanuel Carrilho, PhD, is an Associate Professor at the University of Säo Paulo, Brazil. With more than twenty-five years of experience in separation science, his group is focused on the development of analytical methods and instrumentation for bioanalyses.