In UV-Vis spectroscopy, light passes through the sample, and certain wavelengths are absorbed, causing electronic transitions. The resulting absorption spectrum is recorded and analysed to determine the presence and concentration of specific substances. It is a widely used analytical technique, and its applications extend from nucleic acid analysis to environmental science for detecting water pollutants.
Contrary to the name, nearly all UV-Vis spectrophotometers can measure samples with ultraviolet (190-400 nm), visible (400-750 nm) and NIR (750 – 1100 nm) light giving a total wavelength coverage of 190-1100 nm. There are two main types of UV-Vis spectrometers single-beam and double-beam. In single-beam spectrophotometers, there is only one light path, and manual switching of the sample and reference cuvettes is required. Double beam spectrophotometers have two light paths, and the sample and reference cuvettes are inserted simultaneously, which enables faster operation and more reproducible results.
