Agilent Technologies Infinity 1260 User Manual page 12

1
Introduction to the Refractive Index Detector
How the Detector Operates
According to the formula below small angles of external deflection are
proportional to the difference between the refractive indices of medium 1 and
medium 2.
Where:
• γ = angle of external deflection
• n
• n
Factors that Affect Refractive Index
The refractive index of a medium is affected by a number of factors;
1 Wavelength
2 Density
12
= Refractive index of medium 2
2
= Refractive index of medium 1
1
The refractive index varies with changes in the wavelength of the incident
light beam.
As the density of the medium changes the refractive index changes. At a
fixed wavelength of incident light the changes in refractive index are
generally linear in relation to the changes in medium density.
The density of a medium will be affected by the following factors:
•
Composition (if not a pure substance)
•
Temperature
•
Pressure
Agilent 1260 Infinity RID User Manual