Ultraviolet–visible spectrophotometry (UV-Vis) refers to absorption or reflectance spectroscopy in the ultraviolet–visible spectral region. The absorption or reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region of the electromagnetic spectrum, atoms and molecules undergo electronic transitions. UV-Vis spectroscopy is routinely used in analytical chemistry for the quantitative determination of different analytes, such as transition metal ions, highly conjugated organic compounds, and biological macromolecules. It measures the intensity of light passing through a sample and compares it to the original intensity. The absorbance is then calculated from the transmittance ratio.
In our laboratory we have a Multiskan GO microplate spectrophotometer, which supports endpoint, kinetic, and spectral scanning assays. It reads 96- and 384-well microplates with and without lids. It is also equipped with the μDrop plate, which is designed for measurements of low sample volumes down to 2 μl. The machine has an advanced monochromator system providing a wavelength range from 200 to 1000 nm with a 1 nm step. The microplate chamber is equipped with a temperature control up to 45 °C to enable temperature-sensitive applications such as enzyme kinetics or cellular assays. Shaking speed can be selected to ensure that the samples in the microplate stay homogeneous.