An ultraviolet spectrometer uses ultraviolet light to determine the composition or concentration of a sample. Ultraviolet light cleaves some types of bonds.
The electromagnetic spectrum makes up the entire range of electromagnetic waves, defined by their energy, wavelengths, and frequencies. Energy is the capacity to do work. Ultraviolet light (UV light) is a light wave situated beyond the visible spectrum at its violet end and consisting of radiation having a wavelength shorter than wavelengths of visible light and longer than those of X-rays. The wavelength of UV light is approximately between 100 and 400 nm. Wavelength () is the distance between two identical parts of a wave. Frequency () is the number of oscillations of a wave that occur in a given period of time, usually a second, measured in hertz (Hz). The speed of light (c) is approximately 300,000,000 m/s, and the speed of light is equal to the product of the light’s wavelength and frequency. The period (T) of a wave is the amount of time required for one vibrational cycle, equivalent to the inverse of frequency.
The absorption spectrum is the amount of light absorbed by a compound as a function of the wavelength of light. UV-visible spectroscopy measures the absorption or transmittance of solutions in transparent cells. An ultraviolet spectrometer (UV spectrometer) is a device that measures ultraviolet electromagnetic waves. A sample is dissolved into a solvent and placed in a transparent cell. The UV spectrometer splits UV light into discrete wavelengths that are directed through the sample. The ultraviolet spectrometer measures the change in the amount of the light that is absorbed as it passes through the sample. The molecule or atom absorbs the specific energy from the ultraviolet light of particular wavelengths and changes from an initial ground state energy level to an excited higher energy level state.