What is the Difference Between Chemiluminescence and Fluorescence?

Chemiluminescence and fluorescence are both phenomena that involve the emission of light when an electron relaxes from a higher energy state to a lower energy state. However, the difference between the two lies in the method used to excite the electron to a higher energy state.

• Chemiluminescence: In this process, the electron is in a high-energy state due to the creation of an unstable intermediate in a chemical reaction. Light is released when the intermediate breaks down into the final products of the reaction. Chemiluminescence is the emission of electromagnetic radiation (ultraviolet, visible, or infrared) observed when a chemical reaction yields an electronically excited intermediate which either luminesces or donates its energy to another molecule responsible for the emission. No light source is required to be added to the reaction in order to produce light in a chemiluminescence reaction.
• Fluorescence: In fluorescence, the electron is kicked up to a higher energy state by the addition of a photon. Fluorescence is more complicated because, unlike chemiluminescence, it requires an external excitation source, such as a light source like a xenon arc lamp, which goes through a filter to select for the correct excitation wavelength for the sample. Light emitted from the sample will then go through another filter to select for the correct emission wavelength, which is then detected by a fluorescence spectrophotometer or another specialized digital imager.

In summary, the main difference between chemiluminescence and fluorescence is that chemiluminescence involves the emission of light due to a chemical reaction, while fluorescence involves the emission of light due to the absorption of a photon from an external light source.

Comparative Table: Chemiluminescence vs Fluorescence

Here is a table comparing the differences between chemiluminescence and fluorescence:

Chemiluminescence is the emission of light as a result of a chemical reaction, while fluorescence is the emission of light when a material absorbs electromagnetic radiation and the electrons relax from a higher energy state to a lower energy state. The excitation mechanisms for these two processes are different, with chemiluminescence being excited due to a chemical reaction and fluorescence being excited by electromagnetic radiation. Detection methods also differ, with chemiluminescence being detected using x-ray films, phosphor screens, or specialized digital imagers, and fluorescence being detected using fluorometers or fluorescence spectrophotometers with filters for selecting the correct excitation and emission wavelengths. Chemiluminescence is often used in Western blotting protocols and biosensors, while fluorescence is used in various applications, including fluorescence microscopy, flow cytometry, and fluorescent labeling.