UVvisible

UV-visible spectroscopy, commonly referred to as UV-Vis spectroscopy, is an analytical technique used to measure the absorption of ultraviolet and visible light by a substance. It is widely employed in chemistry, biochemistry, and material science to investigate the electronic structure of molecules and to quantify the concentration of analytes.

In UV-Vis spectroscopy, a sample is exposed to a spectrum of UV and visible wavelengths, typically ranging from 200 to 800 nanometers. As light passes through or reflects from the sample, certain wavelengths are absorbed based on the electronic transitions within the molecules. The resulting absorption spectrum depicts how much light at each wavelength is absorbed, revealing information about the sample's electronic environment.

The technique relies on the principle that molecules with conjugated bonds or specific chromophores absorb light at characteristic wavelengths. These absorption patterns can be used to identify compounds, determine purity, or monitor reactions in real-time. The Beer-Lambert law describes the relationship between absorbance and concentration, enabling quantitative analysis.

UV-Vis spectroscopy instrumentation generally consists of a light source, a monochromator to select specific wavelengths, a sample holder, and a detector to measure transmitted or reflected light. The simplicity, speed, and non-destructive nature of UV-Vis analysis make it a popular choice for routine testing and research.

Limitations include its dependence on chromophores; non-absorbing compounds require derivatization or alternative methods. Despite this, UV-Vis spectroscopy remains a versatile and essential tool for molecular characterization and concentration determination in various scientific fields.