UV Spectrophotometer

UV Spectrophotometer 

Estimation of protein concentration in a given protein preparation is one of the most commonly performed tasks in a biochemistry lab. There are several ways of estimating the protein concentration such as amino acid analysis following acid hydrolysis of the protein; analyzing the changes in the spectral properties of certain dyes in the presence of proteins; and spectrophotometric estimation of the proteins in near or far UV region. Although dye-binding assays and amino acid analysis following acid hydrolysis of the protein can be used for estimating the protein concentration for both pure as well as an unknown mixture of proteins; UV spectroscopic quantitation holds good for the pure proteins. If a protein is pure, UV spectroscopic quantitation is the method of choice because it is easy and less time consuming to perform; furthermore, the protein sample can be recovered back. Absorption of ultraviolet radiation is a general method used for estimating a large number of bio analytes . The region of the electromagnetic radiation ranging from ~10 – 400 nm is identified as the ultraviolet region. For the sake of convenience in referring to the different energies of UV region, it can be divided into three regions:

 • Near UV region (UV region nearest to the visible region; λ ~ 250 – 400 nm)

 • Far UV region (UV region farther to the visible region; λ ~ 190 – 250 nm)

 • Vacuum UV region (λ < 190 nm) 

This division is not strict and you may find slightly different wavelength ranges for these regions.