Search results
Results From The WOW.Com Content Network
The term intrinsic DNA fluorescence refers to the fluorescence emitted directly by DNA when it absorbs ultraviolet (UV) radiation. It contrasts to that stemming from fluorescent labels that are either simply bound to DNA or covalently attached to it, [1] [2] widely used in biological applications; such labels may be chemically modified, not naturally occurring, nucleobases.
The infrared absorption spectrum of NASA laboratory sulfur dioxide ice is compared with the infrared absorption spectra of ices on Jupiter's moon, Io credit NASA, Bernard Schmitt, and UKIRT. Absorption spectroscopy is useful in chemical analysis [5] because of its specificity and its quantitative nature. The specificity of absorption spectra ...
Most elements are first put into a gaseous phase to allow the spectra to be examined although today other methods can be used on different phases. Each element that is diffracted by a prism-like instrument displays either an absorption spectrum or an emission spectrum depending upon whether the element is being cooled or heated. [7]
The color that is seen by our eyes is that of the light not absorbed by the reflecting object within a certain wavelength spectrum of visible light. The chromophore indicates a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum (or in informal contexts, the ...
The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. [1] The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level. The opposite, a decrease of absorbance is called hypochromicity.
These two different types of hemoglobin exhibit different absorption spectra that are normally represented in terms of molar extinction coefficients, as shown in Figure 1. The molar extinction coefficient of Hb has its highest absorption peak at 420 nm and a second peak at 580 nm. Its spectrum then gradually decreases as light wavelength increases.
The classical example of a discrete spectrum (for which the term was first used) is the characteristic set of discrete spectral lines seen in the emission spectrum and absorption spectrum of isolated atoms of a chemical element, which only absorb and emit light at particular wavelengths. The technique of spectroscopy is based on this phenomenon.
The spectra of basic, acid and intermediate pH solutions are shown. The analytical concentration of the dye is the same in all solutions. In spectroscopy, an isosbestic point is a specific wavelength, wavenumber or frequency at which the total absorbance of a sample does not change during a chemical reaction or a physical change of the sample ...