Separations based on either fast very high pressure liquid chromatography (vHPLC) or low-density supercritical fluid chromatography (SFC) cause temperature heterogeneities across the chromatographic column and serious losses in column performance. The limitation of state-of-the-art LC/SFC instruments is that current column ovens allow for too large heat exchange by diffusion and radiation modes from the column wall to the external environment. A simple and drastic solution to this problem is to place the column under strict adiabatic conditions in order to reduce or even to eliminate radial temperature gradients across the column. The column is encapsulated into a high vacuum chamber (pressure &lt;10-4 Torr) and covered with aluminum foil (emissivity coefficient e=0.04 vs. 0.28 for polished stainless steel) in order to eliminate heat losses caused by air both conduction and radiation modes, respectively. In this presentation, we demonstrate the proof-of-concept of such new column technology and report on the various research steps required to design a user-friendly vacuum jacketed column (VJC) capable to deliver the maximum theoretical performance for any extreme experimental conditions. It is shown how VJC columns opened new opportunities towards a better coupling and integration between the eluent preheater, the chromatographic column, and the optical UV cell or the ionization source of mass spectrometers (MS). Experimental data are presented showing how VJC columns can be easily deployable to any optical and MS detectors without column oven while post-column sample dispersion can be reduced to nearly zero. Such improved system integration enables a significant gain in both resolution and sensitivity while keeping all the options offered by MS techniques (flow divert, make-up flow, infusion, lock mass).

Vacuum-Jacketed Columns:  An opportunity for better LC/MS integration

2019 Spring National Meeting

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