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UV-Visible spectroscopy, also known as ultraviolet-visible spectrophotometry, is an analytical technique that measures the absorption of ultraviolet (UV) and visible light by a substance. The technique is based on the interaction of light with the electronic states of molecules. When a molecule absorbs UV or visible light, its electrons are excited from a lower energy level to a higher energy level. The wavelengths of light absorbed by the molecule correspond to the energy difference between these electronic states.

Function: UV-Visible spectroscopy is primarily used to:

Identify and Characterize Compounds:

• Different molecules absorb light at specific wavelengths, producing a characteristic absorption spectrum. This spectrum can be used to identify and characterize the substance.

Determine Concentration:

• The amount of light absorbed by a sample is directly related to the concentration of the absorbing species, according to the Beer-Lambert Law. This makes UV-Visible spectroscopy a powerful tool for quantifying the concentration of analytes in solution.

Analyze Chemical Reactions:

• By measuring the changes in absorption over time, UV-Visible spectroscopy can be used to monitor the progress of chemical reactions.

Study Protein and Nucleic Acid Interactions:

• Biomolecules such as proteins and nucleic acids absorb UV light at specific wavelengths, allowing for their analysis and concentration determination in biochemical studies.

Purity Check:

• The purity of a substance can be assessed by comparing the absorption spectrum of the sample with that of a pure standard.