Capillary Electrophoresis and Microchip Capillary Electrophoresis

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.

Autorentext

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.

Inhalt

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 (FESIMEKC) 32

2.5.3.2 Field-Enhanced Sample Injection with Reverse Migrating Micelles (FESIRMM) 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</p&g...