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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.
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 ...
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 ...
Cary Model 14B Recording Spectrophotometer (front, details almost identical to Model 14) Cary Model 14 Recording Spectrophotometer (back, open) The Cary Model 14 UV-VIS Spectrophotometer was a double beam recording spectrophotometer designed to operate over the wide spectral range of ultraviolet, visible and near infrared wavelengths (UV/Vis/NIR).
[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.
If the instrument is designed to measure the spectrum on an absolute scale rather than a relative one, then it is typically called a spectrophotometer. The majority of spectrophotometers are used in spectral regions near the visible spectrum. A spectrometer that is calibrated for measurement of the incident optical power is called a ...
Infrared spectroscopy is based on the fact that molecules absorb electromagnetic radiation at characteristic frequencies related to their vibrational structure. Infrared (IR) spectroelectrochemistry is a technique that allows the characterization of molecules based on the resistance, stiffness and number of bonds present.
UV–vis spectroscopy sees only chromophores, so other molecules must be prepared for analysis by chemical addition of a chromophore such as anthracene. Two methods are reported: the octant rule and the exciton chirality method. [1] The octant rule was introduced in 1961 by William Moffitt, R. B. Woodward, A. Moscowitz, William Klyne and Carl ...