A filter fluorometer is a type of

fluorometer A fluorometer, fluorimeter or fluormeter is a device used to measure parameters of visible spectrum fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. These parameters ar ...

that may be employed in

fluorescence spectroscopy Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electron ...

. In the fluorometer, a light source emits light of an excitation wavelength that is relevant to the compound to be measured. Filter fluorometers produce specific excitation and emission wavelengths by using optical filters. The filter blocks other wavelengths but transmits wavelengths relevant to the compound. The light passes through the sample to be measured, and a certain wavelength is absorbed while a longer wavelength is emitted. The emitted light is measured by a detector. By changing the optical filter, different substances can be measured.

Applications

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.

Filters

There are two filters for the fluorometer: #The ''primary filter'' or ''excitation filter'' or ''incident light filter'' isolates the wavelength that will cause the compound to

fluoresce Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

(the

incident Incident may refer to: * A property of a graph in graph theory * ''Incident'' (film), a 1948 film noir * Incident (festival), a cultural festival of The National Institute of Technology in Surathkal, Karnataka, India * Incident (Scientology), a ...

light). #The secondary filter isolates the desired emitted light (

fluorescent light A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet lig ...

Choosing the correct filters

The proper selection of filters requires familiarity with the

emission spectrum The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a atomic electron transition, transition from a high energy state to a lower energy st ...

and the

excitation spectrum Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electron ...

. The primary filter is selected to transmit only the wavelengths from the emission spectrum and excitation spectrum that overlap.

References

{{Reflist Spectrometers