Ultraviolet–visible spectroscopy
Ultraviolet–visible spectroscopy (UV-Vis spectroscopy) is a type of absorption spectroscopy in the ultraviolet and visible regions of the electromagnetic spectrum. This technique is used to measure the absorbance of light by a sample, which can provide information about the sample's chemical composition and concentration.
Principle[edit | edit source]
UV-Vis spectroscopy is based on the principle that molecules absorb light at specific wavelengths. When a molecule absorbs UV or visible light, electrons in the molecule are excited from a lower energy level to a higher energy level. The amount of light absorbed at each wavelength is measured and plotted to create an absorption spectrum.
Instrumentation[edit | edit source]
The main components of a UV-Vis spectrophotometer include:
- A light source that emits light in the UV and visible regions.
- A monochromator to select specific wavelengths of light.
- A sample holder where the sample is placed.
- A detector to measure the intensity of transmitted light.
Applications[edit | edit source]
UV-Vis spectroscopy is widely used in various fields, including:
- Chemistry: To determine the concentration of a substance in a solution using Beer-Lambert law.
- Biochemistry: To study the properties of proteins, nucleic acids, and other biomolecules.
- Environmental science: To analyze pollutants in water and air.
- Pharmaceutical industry: To ensure the quality and consistency of drugs.
Beer-Lambert Law[edit | edit source]
The Beer-Lambert law relates the absorbance of light to the properties of the material through which the light is traveling. The law is expressed as: \[ A = \varepsilon \cdot c \cdot l \] where:
- \( A \) is the absorbance,
- \( \varepsilon \) is the molar absorptivity,
- \( c \) is the concentration of the solution,
- \( l \) is the path length of the sample cell.
Advantages and Limitations[edit | edit source]
Advantages[edit | edit source]
- Non-destructive analysis.
- High sensitivity and specificity.
- Rapid and simple to perform.
Limitations[edit | edit source]
- Requires clear and colorless samples.
- Limited to compounds that absorb UV or visible light.
- Interference from other absorbing species in the sample.
See also[edit | edit source]
References[edit | edit source]
External links[edit | edit source]
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
WikiMD's Wellness Encyclopedia |
Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD