Agilent InfinityLab LC Series RID User Manual
18
1
Introduction to the Refractive Index Detector
Detection Principle
Detection Principle
Detector Design
The Agilent 1200 Infinity II Refractive Index Detector is a differential
refractometer that measures the deflection of a light beam due to the difference
in refractive index between the liquids in the sample and reference cells of a
single flow cell.
A beam of light from the lamp passes through a flow cell which is separated
diagonally into sample and reference cells. At the rear of the flow cell a mirror
reflects the light back through the flow cell and via a zero glass, which affects the
path of the light beam, to the light receiver. The light receiver has two diodes
each of which produces an electrical current proportional to the amount of light
that falls upon it (see
Figure 5
Light path
