Description about atomic absorption spectroscopy
Atoms or molecules which are excited to high energy levels can decay to lower levels by emitting radiation emission or luminescence. For atoms excited by a high-temperature energy supply this light emission is usually called nuclear or optical emission atomic-emission spectroscopy, and for atoms excited with light it is known as nuclear fluorescence atomic-fluorescence spectroscopy. Atomic-emission spectroscopy AES uses quantitative measurement of the optical emission from excited atoms to determine analyte concentration. Analyte atoms in solution are aspirated into the excitation area where they are desolated, vaporized and atomized by means of a fire, discharge, or plasma. These high-temperature atomization sources provide sufficient energy to promote the atoms into high energy levels. The atoms decay back to lower levels by emitting light.
In an extremely sophisticated setup, sample prep for the AES is conducted with inductively coupled plasma ICP and this technique requires relatively higher flow rates of specialty gases levels of HI Argon, which would often be provided as numerous cylinder bundles or supplied as liquid and vapourised before use from the tool to ensure uninterrupted operation of the ICP. The normal argon purity level would be 99.998 to 99.999%. Alternately, AES can be combined with gas chromatography GC Where the method would be known to GC-AED. The chromatograph would have HI Helium 6.0 purity level 99.9999percent for the AED plasma and as carrier gas to permit species identification from the atomic emission detector.
Also referred to as flame emission atomic absorption spectroscopy or flame photometry, has found widespread application in elemental analysis. It can be used for both qualitative and quantitative analysis and it is a single element approach. Its most important uses are in the determination of sodium, potassium, lithium and calcium in biological fluids and tissues. The sample has to be converted into free atoms, usually at a high-temperature Excitation source e.g., a fire. Liquid samples are nebulized and carried into the fire by means of a flowing gas. The excitation source has to desolate, atomize and excite the analyte atoms. The fire supplies the adequate energy to promote the atoms into high energy levels. As the atoms decay to their ground point, the emitted radiation passes through the monochromator that isolates the particular wavelength for desired analysis. A photodetector measures the radiant power of the chosen radiation.