1
Introduction to the Detector
System Overview
Agilent InfinityLab ELSD User Manual
10
Detection
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.
Figure 1
Principles of Operation
1. Nebulization
2. Evaporation
3. Detection
