The eluent inlet is connected to the nebulizer via a short length of stainless steel capillary tube. The incoming eluent stream passes through the heated nebulizer and is mixed with the incoming nebulizer gas stream. The mixed gas and eluent stream form an aerosol plume containing a uniform dispersion of droplets that then passes as a continuous flow into the evaporator section. Any larger droplets or the inefficiently nebulized droplets collect in the nebulizer chamber waste trap and then drain off via the waste outlet into a collection bottle.
After nebulization, the atomized spray is propelled through the evaporation tube assisted by the carrier gas. In the evaporator section, the solvent is removed leaving a stream of dry particles of the analyte. A diffuser located in the evaporator assists in the drying of the particles, acting as an efficient heat exchanger, prevents ballistic particles reaching the scattering chamber and randomizes the particle plume. The ELS Detector uses patented gas flow technology in the evaporation zone to aid evaporation at low temperatures. By adding a stream of dry nitrogen (evaporation gas) at the entrance of the evaporator tube less volatile solvents (for example, water) are easily evaporated. This evaporation gas is controlled by the user and facilitates subambient operation.
Light in the optical chamber is passed through the instrument at right angles to the direction of particle flow. A light trap is located opposite the source of light to capture the transmitted incident beam eliminating internal reflections within the instrument body. When pure solvent is being evaporated, only its vapor passes through the light path and the amount of light scattered to the photomultiplier is small and gives a constant baseline response. When a nonvolatile solute is present a particle cloud passes through the light path, causing light to be scattered. This scattered light enters the optical aperture of the detection system and generates a signal response from the photodiode in real time. The quantity of light detected depends on the solute concentration and solute particle size distribution.
base-id: 4344546699
id: 4344546699