Evaporation to Dryness Module

Fig. 4.9 Continuous solvent change-over system for vacuum distillation and redissolution marketed by Technicon under the trade name Evaporation-to-dryness Module. (Courtesy of Technicon).

Dialysis and solvent extraction are the most commonly used precolumn techniques. In an SFA unit specially developed for LC sample preparation to ensure solvent compatibility with the mobile phase, the evaporation to dryness module, sample dissolved in a volatile organic solvent is pumped onto a moving PTFE wire the solvent is evaporated in a stream of hot gas and the residue redissolved in a second solvent compatible with the chromatography system. 

When a non-volatile analyte is dealt with, the vaporization of a liquid phase can be used to remove interferences or facilitate the analytical technique by changing the solvent. Such Is the case with the Evaporatlon-to-Dryness Module (EDM) developed by Technicon, the operational diagram of which is depicted in Fig. 4.9. The liquid sample Is aspirated through a peristaltic pump and poured slowly on a Teflon conveyor belt. For a preset time, a zone of the module Is subjected to extreme vacuum to effect the evaporation of the... 

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