CHROMATOGRAPHIC CRYOFOCUSING AND CRYOTRAPPING WITH THE VORTEX TUBE

Cryofocusing and cryotrapping techniques are the analytical-scale preconcentration or collection of solutes using low temperature, with subsequent solute removal and analysis. Although these methods have been used with many analytical procedures including spectroscopic techniques, the major applications have been in chromatographic methods that involved a wide variety of sample mixtures, including volatile and nonvolatile solutes at trace concentrations. Methods that were used involved headspace analysis, packed and open-tubular columns, and supercritical fluid extraction and chromatography. We describe a simple, entirely pneumatic approach to chromatographic sample cryofocusing-cryotrapping. The two airstreams from a vortex tube (cold and hot, respectively) are used to both chill the cryofocus region of the injector and then to thermally desorb the collected solutes for injection. © 1994 Oxford University Press.