Mindex Ltd
are a official agents for Aurora Instruments for Libya, and Nigeria. Aurora
Instruments Ltd is a manufacturer of analytical instruments for use in the
elemental analysis sector.
Elemental analysis is a process where a
sample of material (eg. soil, waste or drinking water, bodily fluids, minerals,
chemical compounds) is analyzed for its elemental composition.
Analytical chemistry is the analysis of material samples to gain an
understanding of their chemical composition and structure. Atomic absorption
spectroscopy in analytical chemistry is a technique for determining the
concentration of a particular metal element within a sample.
Atomic
Absorption Spectroscopy can be used to analyze the concentration of over 62
different metals in a solution.
Typically, the technique makes use of a
flame to atomize the sample, but other atomizers such as a graphite furnace are
also used. Three steps are involved in turning a liquid sample into an atomic
gas:
Desolvation – the liquid solvent is evaporated,
and the dry sample remains
Vapourisation – the solid
sample vaporizes to a gas
Volatisation – the compounds
making up the sample are broken into free atoms.
The flame is arranged
such that it is laterally long (usually 10cm) and not deep. The height of the
flame must also be controlled by controlling the flow of the fuel mixture. A
beam of light is focused through this flame at its longest axis (the lateral
axis) onto a detector past the flame.
The light that is focused into
the flame is produced by a hollow cathode lamp which is the most common light
source used in atomic absorption (AA) spectroscopy. The wavelength and
intensity of light is dependant on the metal. Therefore, analysis by atomic
absorption spectrometer requires a specific lamp for each element to be
measured.
As the quantity of energy inputted into the flame is known,
and the quantity outputted at the other side (detector) can be measured, it is
possible to calculate how many of these transitions took place, and thus get a
signal that is proportional to the concentration of the element being
measured. |
