|High temperature chromatography: the winning solution allowing both throughput and efficiency?
|Prof Frederic Lynen
Abstract Information :
Physical separation processes requiring the migration of solutes in liquids are inherently slower compared to methods taking place in a low viscosity medium like a gas. The fundamental performance of chromatographic techniques can therefore be increased by reducing diffusional distances, as is done in UHPLC, or by speeding up diffusion processes, as is done in SFC and in elevated temperature HPLC. The latter approaches also allow for the implementation of greener and more cost-effective chromatography. The various possibilities offered by exploiting the benefits of elevated, high and extreme temperatures in liquid chromatography are discussed in this presentation. In the range of elevated temperatures, temperature responsive liquid chromatography (TRLC), whereby columns are packed with particles on which polymers with tunable hydrophobicity are anchored, show significant promise. Such columns allow purely aqueous reversed phase HPLC, whereby retention is controlled through temperature within a mild range of room temperature to 60°C. The possibilities, drawbacks and recent incremental improvements of the technique are compared. Various solutions are thereby explored in order to allow higher throughput and higher peak capacities through TRLC. Alternatively the possibilities offered by the coupling of conventional reversed phase and HILIC columns at higher temperatures (˜60-80°C) are demonstrated. This includes the ability to generate much higher efficiencies (N=100.000) compared to conventional room temperature approaches within conventional analysis times. The potential and challenges presented by novel more hydrothermally stable organo-silica based materials is subsequently demonstrated through fast, high temperature applications allowing operation up to 150°C. Finally extremely stable hydrogenated synthetic micro-dispersed sintered detonation diamond particles are evaluated up to and above 200°C under reversed phase HPLC conditions up to 400°C and 1000 bar and under SFC conditions using only water as mobile phase; this to study the chromatographic behavior and potential under such harsh conditions allowing fast analyte diffusion.