UV-Vis Spectroscopy: Principles and Applications

How does UV-Vis spectroscopy work?

UV-Vis spectroscopy measures how much ultraviolet (UV) and visible light a sample absorbs at specific wavelengths. When light passes through a sample, molecules absorb energy, promoting electrons to higher energy states. The amount of light absorbed is proportional to the concentration of the absorbing species, as described by the Beer-Lambert law. Instruments, known as spectrophotometers, emit light across a range of wavelengths (typically 190–800 nm) and detect transmitted light, generating an absorption spectrum.

What are the key applications in biotech and pharmaceuticals?

In biotech and pharmaceutical development, UV-Vis is routinely used for quantifying nucleic acids (e.g., DNA/RNA via absorbance at 260 nm), proteins (280 nm), and small molecules. It supports quality control by assessing purity (e.g., A260/A280 ratios), verifying batch consistency, and monitoring reaction progress. It is also used in stability studies and in the development of formulations, where changes in absorbance can indicate degradation or aggregation. The technique is non-destructive, rapid, and requires minimal sample preparation, making it ideal for routine lab use.

Related concepts

UV-Vis is often used alongside other analytical methods such as HPLC, NMR, and ELISA for comprehensive characterisation. It is also integral to regulatory compliance, with data supporting CoA, SDS, and batch release documentation under standards like USP, EP, and ISO 17025.