---
title: "Extinction coefficient: research glossary | Sable Peptides"
description: "The extinction coefficient, or molar attenuation coefficient, describes how strongly a substance absorbs light at a particular wavelength per unit concentr"
canonical: https://www.sablepeptides.co.uk/glossary/extinction-coefficient
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

Glossary

# Extinction coefficient

The extinction coefficient, or molar attenuation coefficient, describes how strongly a substance absorbs light at a particular wavelength per unit concentration and path length, usually expressed in M⁻¹cm⁻¹. For peptides at 280 nm it is calculated from aromatic residue content and used to determine solution concentration.

Source: [en.wikipedia.org](https://en.wikipedia.org/wiki/Molar_attenuation_coefficient)

## Related terms

-   [Residue](/glossary/residue)

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