In order to perform metabonomic investigations, it is necessary to generate comprehensive “global” metabolite profiles from complex samples, such as biofluids and tissues/tissue extracts. Analytical technologies based on liquid chromatography coupled to mass spectrometry (LC-MS) are destined to become a major source of global metabolite profiling data. Here, we describe and compare the utility of various analytical strategies and techniques currently used for LC-MS (capillary, high-performance and ultra-performance). We describe current challenges in the application of LC-MS-based techniques for metabonomic analysis.

LC-MS-based methodology for global metabolite profiling in metabonomics/metabolomics

In order to enhance chromatographic performances in terms of efficiency and rapidity, LC has recently evolved in the development of short columns packed with small particles (sub-2 microm) working at high pressures (> 400 bar). This approach has been described 30 years ago according to the fundamental chromatographic equations. However, systems and columns compatible with such high pressures have been introduced in the market in 2004 only. Advantages of small particles working at high pressure will be discussed in terms of sensitivity, efficiency, resolution, and analysis time. Potential problems encountered with high pressure in terms of frictional heating and solvent compressibility will also be discussed even if systems working at a maximum pressure of 1000 bar are not influenced by these parameters and give reliable and reproducible results. Several applications will highlight the potential and interest of this new technology.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jssc.200600189

Fast analysis in liquid chromatography using small particle size and high pressure

The limits of detection (LOD) for capillary electrophoresis (CE) are constrained by the dimensions of the capillary. For example, the small volume of the capillary limits the total volume of sample that can be injected into the capillary. In addition, the reduced pathlength hinders common optical detection methods such as UV detection. Many different techniques have been developed to improve the LOD for CE. In general these techniques are designed to compress analyte bands within the capillary, thereby increasing the volume of sample that can be injected without loss of CE efficiency. This on-line sample preconcentration, generally referred to as stacking, is based on either the manipulation of differences in the electrophoretic mobility of analytes at the boundary of two buffers with differing resistivities or the partitioning of analytes into a stationary or pseudostationary phase. This article will discuss a number of different techniques, including field-amplified sample stacking, large-volume sample stacking, pH-mediated sample stacking, on-column isotachophoresis, chromatographic preconcentration, sample stacking for micellar electrokinetic chromatography, and sweeping.

On-line preconcentration methods for capillary electrophoresis.

Evaluation of ultra performance liquid chromatography Part I. Possibilities and limitations

Recent developments in chromatographic supports and instrumentation for liquid chromatography (LC) are enabling rapid and highly efficient separations Various analytical strategies have been proposed, for example the use of silica-based monolithic supports, elevated mobile phase temperatures, and columns packed with sub-3 microm superficially porous particles (fused core) or with sub-2 microm porous particles for use in ultra-high-pressure LC (UHPLC) The purpose of this review is to describe and compare these approaches in terms of throughput and resolving power, using kinetic data gathered for compounds with molecular weights ranging between 200 and 1300 g mol(-1) in isocratic and gradient modes This study demonstrates that the best analytical strategy should be selected on the basis of the analytical problem (eg, isocratic vs gradient, throughput vs efficiency) and the properties of the analyte UHPLC and fused-core technologies are quite promising for small-molecular-weight compounds, but increasing the mobile phase temperature is useful for larger molecules, for example peptides

/pdf/new-trends-in-fast-and-high-resolution-liquid-chromatography-4tywj3zh4i.pdf

New trends in fast and high-resolution liquid chromatography: a critical comparison of existing approaches.

A new, empirical approach is introduced to correct for the varying response of aerosol-based detectors with the varying composition of the mobile phase during gradient elution in HPLC. A Corona charged aerosol detector was used in the experiments. The detector is characterized by a nearly universal response at a given, constant mobile-phase composition for sufficiently nonvolatile analytes. A second pump was used to deliver an exactly inverse gradient compared to the analytical HPLC system, and both flows were mixed in a tee piece before introduction to the Corona detector. The approach proposed made it possible to extend the universal response from isocratic to gradient elution conditions in HPLC, vastly improving the usefulness of this detection technique. The constant response of the detector obtained in this way was first demonstrated in flow injection analysis. Very similar calibration curves were obtained for six sulfonamide drugs after mobile-phase compensation. The approach was also applied to gra...

Universal response in liquid chromatography using charged aerosol detection.

Influence of frictional heating on temperature gradients in ultra-high-pressure liquid chromatography on 2.1mm I.D. columns.

High-efficiency liquid chromatography on conventional columns and instrumentation by using temperature as a variable. I. Experiments with 25 cm × 4.6 mm I.D., 5 μm ODS columns

High efficiency liquid chromatography on conventional columns and instrumentation by using temperature as a variable. Kinetic plots and experimental verification.

Roman Szucs

Papers

Evaluation of ultra performance liquid chromatography Part I. Possibilities and limitations

Universal response in liquid chromatography using charged aerosol detection.

Influence of frictional heating on temperature gradients in ultra-high-pressure liquid chromatography on 2.1mm I.D. columns.

High-efficiency liquid chromatography on conventional columns and instrumentation by using temperature as a variable. I. Experiments with 25 cm × 4.6 mm I.D., 5 μm ODS columns

High efficiency liquid chromatography on conventional columns and instrumentation by using temperature as a variable. Kinetic plots and experimental verification.