Chapter 3 - Introduction - Page 89

     The wide variety of chromatographic techniques developed and improved over the past three decades (Ward and Ward, 2010) allows researchers at the moment to address and resolve most of the problems related to the separation of molecular or ionic species, from both preparative and analytical points of view. Examples of preparative separations have been performed for synthetic products, bioactive molecules extracted from biological sources, and for racemates of chiral drugs (Francotte, 2009; Sticher, 2008; Bucar et al., 2013). Typical analytical separations have been applied for the quantification of compounds in complex mixtures, the determination of enantiomeric excess of scalemic mixtures, and the identification of organic compounds by hyphenated chromatographic techniques (Wilkins, 1983; Holt et al., 1997; Ellis and Roberts, 1997; Guetens et al., 2002a,b).
     A peculiar and elegant application of chromatography has also been devoted to supramolecular chemistry, where it allows calculation of the thermodynamic stability of supramolecular adducts and the association constants of hosteguest complexes (Ciogli et al., 2013; Gasparrini et al., 1997b, 2002b). Moreover, chromatography has recently been used for the study of internal molecular dynamics of a range of
stereochemically labile organic compounds and for the determination of kinetic parameters of the pertinent equilibrium (i.e., the reversible isomerization of one enantiomer into the other) (Ceccacci
et al., 2003; D’Acquarica et al., 2006).
     In this context, the implementation of highly efficient chromatographic techniques pushed to their extreme limits may represent a very effective tool to achieve thermodynamic and kinetic data (Krupcik et al., 2003; Katsanos et al., 1998; Wolf, 2005, 2008), when experimental conditions make the use of alternative methods difficult or impossible, such as dynamic nuclear magnetic resonance (DNMR) spectroscopy and batchwise classical approaches.
     This chapter provides a basic overview of the concepts behind the determination of reaction rate constants and activation barriers by dynamic chromatography (DC). Several examples of the application of such technique in the study of model stereochemically labile compounds have been provided as well.

Click on the thumbnail graphics below to access the original full-size figure.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 1

Figure 3.1

Line-shape of chromatograms showed by isomeric IA and IB species that undergo interconversion during elution through the chromatographic column.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 2

Figure 3.2

Thermodynamic cycle involved during dynamic chromatography experiments (for the meaning of symbols, see text).

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 3

Figure 3.3

Classical stochastic model.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 4

Figure 3.4

Relationships between time of simulation (seconds) of dynamic chromatograms and chromatographic efficiency (number of theoretical plates) involved in the theoretical plates model and classical stochastic model.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 5

Figure 3.5

Calculation of free energy activation barriers and their enthalpic and entropic contributions.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 6

Figure 3.6

Activation entropies (deltaS, e.u.) and free energies (deltaG, kcal/mol) of conformational and configurational isomerizations calculated by DHPLC and DHRGC.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques -  Chapter 3 Figure 7

Figure 3.7

Optimal range of applicability of dynamic chromatography [including gas chromatography (GC), high-performance liquid chromatography (HPLC), and ultra-high performance liquid chromatography (UHPLC)] and dynamic nuclear magnetic resonance (DNMR) techniques in the determination of activation barriers for isomerization processes.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques -  Chapter 3 Figure 8

Figure 3.8

Chemical structure of the DACH-DNB CSP.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques -  Chapter 3 Figure 9

Figure 3.9

Representation of the van Deemter plot of the column packed with 1.9 um DACH-DNB CSP.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 10

Figure 3.10

Ultra-fast enantioresolution of N-(1-(naphthalen-5 yl) ethyl)-1-naphthamide on the 1.9 um DACH-DNB CSP packed into a stainless-steel (50 x 4.1 mm I.D.) column.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 11

Figure 3.11

Van Deemter plot for chiral and achiral compounds on Whelk-O1 chiral stationary phases. (A) 250 x 4.6 mm I.D. column packed with fully-porous particles of 5-um average size. (B) 100 x 4.6 mm I.D. column packed with fully-porous particles of 1.7-um average size. Eluent: hexane/dichloromethane 8:2 (v/v) + 3% methanol.

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 12

Figure 3.12

Comparison of the ultra-high performance liquid chromatography (UHPLC) technique advantages with the well consolidated high-performance liquid chromatography (HPLC).

Handbook of Advanced Chromatography / Mass Spectrometry Techniques - Chapter 3 Figure 13

Figure 3.13

Evidence of indirect perturbing SPIPC effect displayed by the racemic version of the DACH-DNB stationary phase on the diastereomerization rate constants of a hindered secondary aryl phosphine oxide.

Overview of the Contents:

The Handbook of Advanced Chromatography /Mass Spectrometry Techniques is a compendium of new and advanced analytical techniques that have been developed in recent years for analysis of all types of molecules in a variety of complex matrices, from foods to fuel to pharmaceuticals and more. Focusing on areas that are becoming widely used or growing rapidly, this is a comprehensive volume that describes both theoretical and practical aspects of advanced methods for analysis. Written by authors who have published the foundational works in the field, the chapters have an emphasis on lipids, but reach a broader audience by including advanced analytical techniques applied to a variety of fields.


Handbook of Advanced Chromatography / Mass Spectrometry Techniques

Key Features

Contains both practical and theoretical knowledge, providing core understanding for implementing modern chromatographic and mass spectrometric techniques Presents chapters on the most popular and fastest-growing new techniques being implemented in diverse areas of research.


Handbook of Advanced Chromatography / Mass Spectrometry Techniques

Table of Contents

The Chapters are listed above. Additional links to the fully enumerated Table of Contents will be added soon.

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Handbook of Advanced Chromatography / Mass Spectrometry Techniques

Expected Readership

The Handbook is intended for upper level undergraduate students and graduate students, researchers, technicians, and scientists.It is also well suited for advanced analytical instrumentation students as well as for analysts seeking additional knowledge or a deeper understanding of familiar techniques.


Handbook of Advanced Chromatography / Mass Spectrometry Techniques

Book Details

No. of pages: 520
Copyright: © Academic Press and AOCS Press 2017
Published: September 11th 2017
eBook ISBN: 9780128117330
Paperback ISBN: 9780128117323