Uv-Visible Spectroscopy Flashcards
Can be used to identify the presence of….
Organic substances
Uv-vis spec is based on….
Transitions within atoms.
Two advantages of uv vis spec…
It can be portable. Non destructive.
Can be used in the biuret test, as both solutions are coloured, to calculate….
The concentrations of proteins.
Used in the wavelength region of…… nm
200 nm - 800 nm
Can be used to distinguish between molecules if…..
The spectrums are significantly different.
Larger molecules have a more complex absorption spectra, this leads to certain functional groups in molecules having a….
Characteristic absorption spectrum in visible range as each group has a specific colour.
Uv vis spec is the study of….
The absorption of light in the uv and visible regions where electronic transitions occur.
A lack of distinctive peaks in the spectra is because of….
Chemical bonds of the compound. The equipment is sensitive enough to pick out individual peaks.
How does a uv vis spectrophotometer work?
Two light sources, uv and vis, pass through a monochromator (diffraction grating) to produce light of a single wavelength. The wavelength is split by a half a mirror. One beam passes through sample cell, the other through a reference cell. Intensities of emerging beams are measured by a CDD detector. The incoming light is converted into a current. Greater light intensity = greater current. Transmitted light is converted into and absorb acne value of the sample.
