Handbook of Advanced Chromatography /Mass Spectrometry Techniques

Michal Holcapek, Wm. Craig Byrdwell

• Publisher: Academic Press and AOCS Press
• Year: 2017
• Print ISBN: 9780128117323
• eBook ISBN: 9780128117330
• Topic: Technology & Engineering
• Subtopic: Industrial & Technical Chemistry
• Index: Technology & Engineering

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 is the ideal reference for those just entering the analytical fields covered, but also for those experienced analysts who want a combination of an overview of the techniques plus specific and pragmatic details not often covered in journal reports. The authors provide, in one source, a synthesis of knowledge that is scattered across a multitude of literature articles. The combination of pragmatic hints and tips with theoretical concepts and demonstrated applications provides both breadth and depth to produce a valuable and enduring reference manual. It is well suited for advanced analytical instrumentation students as well as for analysts seeking additional knowledge or a deeper understanding of familiar techniques.- Includes UHPLC, HILIC, nano-liquid chromatographic separations, two-dimensional LC-MS (LCxLC), multiple parallel MS, 2D-GC (GCxGC) methodologies for lipids analysis, and more- 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

Chapter 1

Theory and Practice of UHPLC and UHPLC–MS

Davy Guillarme^1,2, and Jean-Luc Veuthey^{1,2 1}University of Geneva, Geneva, Switzerland ²University of Lausanne, Lausanne, Switzerland

Abstract

Ultrahigh-pressure (or performance) liquid chromatography (UHPLC) consists of using columns packed with sub-2 μm particles, in conjunction with a system that withstands very high pressures (up to 1500 bar). The goal of this chromatographic approach is to increase sample throughput and/or peak capacity. This strategy became commercially available in 2004 and since then, a large variety of UHPLC systems and columns packed with sub-2 μm particles have been introduced by numerous providers. In this chapter, various aspects of UHPLC will be discussed, such as the theoretical advantages of working with reduced particle sizes in liquid chromatography (LC), the constraints in terms of instrumentation, the effect of elevated pressure on mobile phase properties, a comparison with other existing strategies to attain ultrafast or highly efficient separations, the rules for method transfer between high-pressure liquid chromatography and UHPLC, and finally some applications of UHPLC–MS in bioanalysis, multiresidue screening, and metabolomics.

Keywords

Bioanalysis; Frictional heating; Metabolomics; Method transfer; Multiresidue screening; UHPLC; UHPLC–MS

1. Introduction

Reversed-phase liquid chromatography (RPLC) is currently one of the most widely used separation techniques. During the last few years, some substantial improvements, such as innovative supports and instrumentation, have been brought forth to perform high-throughput analyses and highly efficient separations in RPLC (Guillarme et al., 2007b; Novakova et al., 2006). Such advances were mainly driven by the need to handle either a growing number of analyses or more complex samples.

Regarding high-throughput separations, there is a growing demand in numerous fields, including toxicology, doping, forensics, clinical chemistry, and environmental analyses, where the delivery time response must be reduced as much as possible. The pharmaceutical field, with its need for enhanced productivity and reduced costs, is certainly the main driving force for faster separations (Wren and Tchelitcheff, 2006). Because of the high number of analyses required for common pharmaceutical applications, such as purity assays, pharmacokinetic studies, and quality control, rapid analytical procedures (less than 5 min including equilibration time) are often mandatory (Al-Sayah et al., 2008).

Highly efficient separations are also necessary for many applications, including proteomics, plant extract analysis, and metabolomics, which all deal with very complex samples, such as biological samples, tryptic digests, or natural plant extracts (Grata et al., 2008; Petricoin and Liotta, 2004). With such difficult samples, conventional high-pressure liquid chromatography (HPLC) systems present some obvious limitations.

Among the different strategies used to achieve fast and high-resolution separations, ultrahigh-pressure liquid chromatography (UHPLC) has been rapidly recognized as a powerful and robust analytical tool. As shown in Fig. 1.1, the number of articles published in the fields of UHPLC and UHPLC–mass spectrometry (MS) has risen very quickly since 2004. Thus, in this chapter, the possibility to speed up and/or attain highly efficient separations will be demonstrated, using the UHPLC strategy in combination with UV as well as MS detectors. This chapter will also discuss the advantages and drawbacks of this approach, in comparison with other existing techniques.

Figure 1.1 Number of papers published each year in the field of ultrahigh-pressure liquid chromatography (UHPLC) and UHPLC–mass spectrometry (MS), since 2004. Before this date, only few papers were published by Jorgenson's and Lee's groups. Blue bars (light gray in print versions) were obtained with keyword “UHPLC”, whereas red bars (dark gray in print versions) were obtained with an additional filter (keyword “MS”). From Scifinder scholar 2016 search of the chemical abstracts database. Date of information gathering: August 2016.

2. Brief Description of Ultrahigh-Pressure Liquid Chromatography and Historical Background

2.1. Interest in Small Particles in Liquid Chromatography

In liquid chromatography (LC), it is well established that a reduction of particle size (d_p) provides an important gain in chromatographic performance (Knox, 1977; Knox and Saleeem, 1969; Poppe, 1997). Indeed, the reduction of d_p allows faster separations as well as higher plate counts. Since the beginning of LC, there has been a continuing progression in the reduction of particle size that has culminated in the commercialization of columns packed with sub-2 μm particles (Table 1.1). According to Eqs. (1.1) and (1.2), these small particles lead to significant improvements in terms of (1) efficiency because N (number of theoretical plates) is inversely proportional to d_p, and (2) time reduction because the optimal mobile phase linear velocity (u) is inversely proportional to particle diameter.

N=Lh·dp

(1.1)

where, L is the column length, h the reduced plate height (generally between 2 and 3), and d_p the particle size.

u=v·Dmdp

(1.2)

where, v is the reduced linear velocity and D_m the diffusion coefficient of the solute into the mobile phase.

Table 1.1

Evolution of Particles Size in Liquid Chromatography

Years	Particle Size (μm)	Plates/15 cm
1950s	100	200
1967	50	1000
1972	10	6000
1985	5	12,000
1992	3–3.5	22,000
1996^a	1.5	30,000
2000	2.5	25,000
2004	1.7	30,000

^a Nonporous silica or resins.

Adapted from Majo...

Table of contents

• Cover image
• Title page
• Table of Contents
• Dedication
• Copyright
• List of Contributors
• Preface
• Chapter 1. Theory and Practice of UHPLC and UHPLC–MS
• Chapter 2. Advances in Hydrophilic Interaction Liquid Chromatography
• Chapter 3. Chiral Separations. Chiral Dynamic Chromatography in the Study of Stereolabile Compounds
• Chapter 4. Silver-Ion Liquid Chromatography–Mass Spectrometry
• Chapter 5. Porous Monolithic Layers and Mass Spectrometry
• Chapter 6. New Materials for Stationary Phases in Liquid Chromatography/Mass Spectrometry
• Chapter 7. Introduction to Two-Dimensional Liquid Chromatography—Theory and Practice
• Chapter 8. Recent Advances in Comprehensive Two-Dimensional Liquid Chromatography for the Analysis of Natural Products
• Chapter 9. Nano-Liquid Chromatographic Separations
• Chapter 10. Multiple Parallel Mass Spectrometry for Liquid Chromatography
• Chapter 11. Comprehensive Gas Chromatography Methodologies for the Analysis of Lipids
• Chapter 12. Ultra-High Performance Supercritical Fluid Chromatography–Mass Spectrometry
• Index