Much can be gained by evaluating separations at their limits. In this talk we discuss recent work that pushes the limits of separation speed, using microchip electrophoresis, and the effects of pressure in UHPLC.<br/>Microchip electrophoresis enables high speed separations on small samples which opens new possibilities for chemical analysis. We have explored new ways of using microchip electrophoresis for protein analysis related to high-throughput screening (HTS) of enzymes and protein-protein interactions. We have recently demonstrated that we can separate protein-protein complexes involved in intracellular signaling to generate quantitative information on binding and selectivity. For proteins that dissociate, we have investigated protein-cross-linking capillary electrophoresis (PXCE). Assays in a few seconds are possible by both approaches. We have also demonstrated fast (&lt; 1 s) separations of substrates and products from enzymes allowing rapid enzyme assays. The high speed of the assays suggests they could be used in HTS for drug discovery. To achieve this, we have developed a droplet microfluidic system that allows discrete samples to be rapidly loaded in sequence onto a chip for injection and separation. Using this method over 1000 injections have been achieved in 17 min. Preliminary results suggest the method is stable enough for HTS opening the door to robust HTS of protein-protein interactions and enzyme activity.<br/>Another extreme that we have explored is high pressure for LC. It is well-known that smaller particles and longer columns, which provide higher resolution, require higher pressure for flow in LC. As a result, advances in LC systems have been made that allow operation up to 15,000 psi. We have experimented with systems that operate up to 40,000 psi. We demonstrate that the higher resolving power allows improved chemical information content for complex lipid samples.

Separations at extreme conditions: Fast and high pressure

2019 Spring National Meeting

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