Polymer Laboratories Limited

Nathan James Wrench

Stephen J O'Donohue

Paul Emil Claes

Frank P Warner

An improved evaporative light scattering detector apparatus for volatile samples is provided. Conventionally incomplete evaporation of the mobile phase (solvent) cannot be achieved for volatile samples as solvent cannot be fully removed at low temperature because the vapor becomes saturated. At higher temperatures the samples evaporate without forming an aerosol. By adding a dry evaporator gas to the sample before entering a drift tube avoids saturation of the vapor and permits complete evaporation of the solvent at low temperatures.

Evaporative light scattering detector

An evaporative light scattering detector (1) has a solvent nebulizer (4) through which an atomised spray of solute solvent solution passes, a heated evaporation chamber (5) and a detector system (6). A diffuser trapping device (7), supported by fine wires, is positioned in the evaporation chamber(5) at about two fifths of the height of the chamber from the top. The diffuser trapping device (7) is made from randomly coiled stainless steel ribbon which gives it a large surface area. The detection system (6) is positioned at the bottom of the evaporation chamber through which a beam of collimated light passes and is scattered by the solvent and detected by a light sensitive device (14). The diffuser trapping device (7) aids evaporation of the solvent and prevents large particles from travelling further down the evaporation chamber (5).

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Bishops Castle, United Kingdom

Nathan James Wrench