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Ultraviolet-visible (UV-vis) spectroscopy involves energy levels that excite electronic transitions. Absorption of UV-vis light excites molecules that are in ground-states to their excited-states. [5] Visible region 400–700 nm spectrophotometry is used extensively in colorimetry science. It is a known fact that it operates best at the range ...
A UV-Vis spectrophotometer is an analytical instrument that measures the amount of ultraviolet (UV) and visible light that is absorbed by a sample. It is a widely used technique in chemistry, biochemistry, and other fields, to identify and quantify compounds in a variety of samples.
The most common UV-Vis detectors used are variable wavelength detectors (VWD), photo diode array detectors (PDA), and diode array detectors (DAD). [4] Variable wavelength detectors decide in advance which wavelength is needed for the detection. Its absorbance as function of time is collected in a graphic format called a chromatogram. [5]
[17]: 18 Its designation as a "UV–Vis" spectrophotometer indicates its ability to measure light in both the visible and ultraviolet spectra. [ 29 ] The DU was the first commercially viable scientific instrument for measuring the amount of ultraviolet light absorbed by a substance.
With the aid of these rules the UV absorption maximum can be predicted, for example in these two compounds: [8] In the compound on the left, the base value is 214 nm (a heteroannular diene). This diene group has 4 alkyl substituents (labeled 1,2,3,4) and the double bond in one ring is exocyclic to the other (adding 5 nm for an exocyclic double ...
Absorption spectrum of an aqueous solution of potassium permanganate.The spectrum consists of a series of overlapping lines belonging to a vibronic progression. Spectral line shape or spectral line profile describes the form of an electromagnetic spectrum in the vicinity of a spectral line – a region of stronger or weaker intensity in the spectrum.
Ultraviolet-visible absorption spectroelectrochemistry is a technique that studies the absorption of electromagnetic radiation in the UV-Vis regions of the spectrum, providing molecular information related to the electronic levels of molecules. [10] It provides qualitative as well as quantitative information.
For UV-Vis spectroelectrochemistry, spectrometer must be specific for UV-Vis spectral region. Potentiostat / Galvanostat : electronic device that allows controlling the working electrode potential regarding to the reference electrode or controlling the current that passes respect to the auxiliary electrode .