Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) involves the spectroscopy of photons in the UV-visible region. This means it uses light in the visible and adjacent (near ultraviolet (UV) and near infrared (NIR)) ranges. The absorption in the visible ranges directly affects the color of the chemicals involved. In this region of the electromagnetic spectrum, molecules undergo electronic transitions. This technique is complementary to fluorescence spectroscopy, in that fluorescence deals with transitions from the excited state to the ground state, while absorption measures transitions from the ground state to the excited state.
Perkin Elmer Lambda 900 UV-VIS/NIR
The Perkin Elmer Lamda 900 UV/VIS/NIR spectrometer is a double-beam, double monochromator ratio recording system with pre-aligned tungsten-halogen and deuterium lamps as sources. The wavelength is from 175 to 3300nm with an accuracy of 0.08 nm in the UV-Visible region and 0.3nm in the NIR region guaranteed. It has a photometric range of +/-6 in absorbance mode.
Accessories available include a 60 mm Spectralon coated integrating sphere with a range from 200 to 2500 nm for measurement of samples of high optical density. A common-beam depolariser for measurements with depolarised light in the 190 to 2600 nm range is also available.