By changing the optical filter, different substances can be measured.
[1] Filter fluorometers can be highly sensitive, so are well suited to precise scientific research.
The optical filters are relatively inexpensive and are easy to change, so filter fluorometers are commonly used in experimental applications which repeatedly measure different compounds.
There are two filters for the fluorometer: The proper selection of filters requires familiarity with the emission spectrum and the excitation spectrum.
The primary filter is selected to transmit only the wavelengths from the emission spectrum and excitation spectrum that overlap.