Difference Between Fluorophore and Chromophore

The key difference between fluorophore and chromophore is that fluorophore is a fluorescent chemical compound whereas chromophore is not a fluorescent compound. It is a part of a chemical compound that is responsible for the color in that molecule.

There are many applications of fluorophores due to its ability to re-emit light upon excitations that occur due to a light source. Some applications include using as a dye or staining agent, as a substrate for enzymes, as a tracer in fluids, etc.

1. Overview and Key Difference
2. What is Fluorophore
3. What is Chromophore
4. Side by Side Comparison – Fluorophore vs Chromophore in Tabular Form
5. Summary

What is Fluorophore?

A fluorophore is a fluorescent chemical compound that can re-emit light upon excitations that occur due to a light source. These compounds get this property due to the presence of several aromatic groups, which are combined with each other or planar/cyclic molecules with several pi bonds (double bonds). These compounds can absorb light energy (of a certain wavelength) and can re-emit this energy as a longer wavelength.

The wavelengths that are absorbed by these compounds depends on the chemical structure of the fluorophore. Usually, these compounds are small, organic compounds, but there can be larger compounds as well. Ex: proteins like green florescent protein.

Difference Between Fluorophore and Chromophore

Figure 01: Fluorescence under UV Radiation

Examples of Flurophore

Some common examples for fluorophores are as follows:

Xanthene derivatives such as fluorescein
Cyanine
Naphthalene derivatives
Coumarin derivatives
Pyrene derivatives such as cascade blue
Anthracene derivatives

What is Chromophore?

Chromophore is a part of a molecule, which is responsible for the color of that molecule. This region of molecules has an energy difference between two separate molecular orbitals which falls within the wavelength range of the visible spectrum. Then, when visible light hits this region, it absorbs the light. This causes the excitations of electrons from a ground state to an excited state. Therefore the color that we see is the color that is not absorbed by the chromophore.

In biological molecules, a chromophore is a region which undergoes conformational changes of the molecule when hit by light. Conjugated pi systems often serve as chromophores. A conjugated pi system has single bonds and double bonds in an alternating pattern. These systems often occur in aromatic compounds.

What is the Difference Between Fluorophore and Chromophore?

A fluorophore is a fluorescent chemical compound that can re-emit light upon excitations that occur due to a light source. Chromophore is a part of a molecule that is responsible for the color of that molecule. This is the main difference between fluorophore and chromophore.

Summary – Fluorophore vs Chromophore

Fluorophores and chromophores are the chemical species responsible for visible effects in compounds. The difference between fluorophore and chromophore is that fluorophore is a fluorescent chemical compound whereas chromophore is not a fluorescent compound.

Reference:

1. “Fluorophore.” Wikipedia, Wikimedia Foundation, 10 June 2018. Available here
2. “Chromophore.” Wikipedia, Wikimedia Foundation, 10 Apr. 2018. Available here