Ultra Violet (UV) Spectroscopy
All atoms absorb in the Ultraviolet (UV) region because these photons are energetic enough to excite outer electrons. If the frequency is high enough, photoionization takes place. UV spectroscopy is also used in quantifying protein and DNA concentration as well as the ratio of protein to DNA concentration in a solution. Several amino acids usually found in protein, such as tryptophan, absorb light in the 280 nm range and DNA absorbs light in the 260 nm range. For this reason, the ratio of 260/280 nm absorbance is a good general indicator of the relative purity of a solution in terms of these two macromolecules. Reasonable estimates of protein or DNA concentration can also be made this way using Beer's law.
We have a Varian Cary-50 spectrometer [03.130] available that has a temperature controlled cell holder.
As an accessory there is an external probe available with a light guide.
Contact: dr. D.W.P.M. Lowik (Dennis)