Ultraviolet Visible (UV-Vis) Spectrophotometry
Ultraviolet visible (UV-Vis) spectrophotometers use a light source to illuminate a sample with light across the UV to the visible wavelength range (typically 190 to 900nm). The instruments then measure the light absorbed, transmitted, or reflected by the sample at each wavelength. Some spectrophotometers have an extended wavelength range, into the near-infrared (NIR) (800 to 3200 nm). The detector then produces the sample's unique UV Vis spectrum (also known as the absorption spectrum). A UV-Vis spectrophotometer measures the intensity of light transmitted through a sample compared to a reference measurement of the incident light source. According to Beer-Lambert Law, the amount of light absorbed is directly proportional to the concentration of the sample and the distance the light travels through the sample. UV- Vis spectrophotometers are therefore capable to determine the concentration of specific analytes by controlling the analysis wavelengths and the path length.
Ultraviolet Visible (UV-Vis) Spectrophotometry is useful for several types of analysis, including for:
- Identify molecules in a solid or liquid sample
- Quantitative analysis of a specific analyte
- Determine the concentration of a particular molecule in solution
- Characterize the absorbance or transmittance through a liquid or solid over a range of wavelengths
- Characterize the reflectance properties of a surface or measuring the colour of a material
- Study chemical reactions or biological processes.