Combinatorial explosion in the separation sciences

von Prof. Dr. Gérard Hopfgartner

In the analytical sciences one of the major goals is to develop and validate methods for the identi­fication and quantification of molecules in complex samples, in order to support investigations in the pharmaceutical sciences, environmental sciences, food sciences, biology and medicine. A typical workflow consists in isolating the analyte from the matrix, separating it from other similar constituents and selectively identifying them. One of the key separation techniques is chromato­graphy, which was pioneered by Mikhail ­S. Tsvet in 1900. Tsvet separated compounds of leaf pigments, extracted from plants using a solvent, in a column packed with particles. Over the years the technique has evolved by working with higher pressures, and has given rise to the acronym HPLC, standing for high pressure ­liquid chromatography, which is now one of the major techniques in the separation sciences. Today operating pressures in range of 600 to 1600 bar are routine. Using smaller particle geometry, resulting in improved separation resolution, various particle chemistries have been developed, making it possible to use different separation mechanisms to cope with the analysis of both small molecules and macromolecules. On-line light scattering, ultraviolet and fluorescence spectroscopy are the most commonly used detection methods. The ­development of atmospheric pressure ionisation techniques (in particular, electrospray ionisation) has given rise to the coupling of ­ultra-pressure liquid chroma­tography and mass spectrometry. This combination has raised standards in separation power and detection, opening new avenues in the multi-­components analysis that is mandatory for proteomic and metabolomic ­i­nvestigations. In addition, the ­integration of real time multi-­dimensional liquid chromatography, ion mobility spectrometry and tandem mass spectrometry adds several dimensions in sample analysis. Ideally, one would like to gather as much information as possible from a single analysis, and a coupling or combination of techniques is highly desirable to cope with these challenges, resulting in a combinatorial explosion of possible approaches. While high quality information is required to push limits in the sciences, the development of high sample throughput and miniaturisation ­approaches in various areas will be needed in order to take full advantage of these new analytical tools. Many of these topics, including fundamental aspects of separation sciences and combinations involving mass spectrometry and high-end applications, will be discussed between academic, industrial, young and established scientists from all over the world at the 42nd International Symposium on High Performance Liquid Phase Separations and Related Techniques, to be held from 21 to 25 June at the International Conference Centre (CICG) in Geneva, Switzerland.

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