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Water - Solubility - Ions

Instrumental Methods
Ultraviolet Spectroscopy - Identifying Compounds.

Some substances absorb ultraviolet (or visible) light.
The wavelength of the light which is absorbed
is different for different compounds.

In ultraviolet spectroscopy all of the different wavelengths
of ultraviolet light are passed through a substance
and the instrument produces an ultraviolet spectrum
showing peaks where the light has been absorbed.

Ultraviolet Spectrum

The compound can be identified by a computer
which compares the shape of the ultraviolet spectrum
with the spectrum of thousands of known materials.
The area of the peak shows the concentration of
the substance (how much is present).

Ultraviolet spectroscopy can identify compounds
such as nitrate in water
and may be used by environmental agencies
to monitor the quality of river and drinking water.

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