Spectrophotometry is an analytical, qualitative and quantitative technique which allows recognition and quantization of a substance based on its absorption spectrum of light. The spectrophotometric analysis is applicable, with certain expedients, to all substances; if the test substance is itself light-absorbing at the wavelength choice is possible a direct measurement, if it is not then it can participate in a chemical reaction in which the substance itself or an its derivative reacts with a dye giving a colored end product. The UV-Vis spectrophotometer consists of the following components:
- a light source which gives rise to a polychromatic radiation in a certain range of wavelengths (tungsten filament lamp for visible light, deuterium lamp for ultraviolet radiation)
- a wavelength selector or monochromator which solves the polychromatic beam in radiations of a determined wavelength
- an holder for the introduction of the cuvette
- a photoelectric cell on which affects the beam emerging from the testing solution;
- an amplification system of the electric current emitted by the photocell
- a galvanometer for measuring the electric curren.
Concentration measurements, Determination of enzyme kinetics, Absorption spectra to identify chromophore groups and molecules, Measurement of color.