Salient Features of AES:

• In atomic emission spectrometry (AES) a reproducible and representative amount of the sample is introduced into an atomization-excitation source wherein it is converted into atomic vapours of the analyte in excited state. The radiation emitted from these is characteristic of the constituents of the sample.
• The AES is a versatile method due to the availability of a wide range of atomization-excitation sources. Presently, plasma is the most used source. It is high energy source which is an electrically neutral conducting gaseous mixture having a significant concentration of cations and electrons.
• The plasma can be sustained by supplying energy from a suitable external source. Depending on the power sources employed, there are three different kinds of plasmas. Those are the inductively coupled plasma (ICP), direct current plasma (DCP) and the microwave induced plasma (MIP). These plasmas use radio frequency and direct current and microwave radiation respectively as the power sources.
• As the energy of the plasma source is quite high, it ensures the excitation of a atoms of all the component present within the analyte that emit EM radiation characteristic of different elements. Therefore, it is a multielement technique.
• Argon gas is generally employed as plasma gas due to its inertness, simple emission spectrum, moderately low thermal conductivity, and good natural abundance.
• There are two types of spectrometers are used for ICP-AES. These are sequential spectrometers and simultaneous spectrometers depending on whether the emitted radiation is measured sequentially or simultaneously.
• In ICP-AES the spectral interference because of the line-rich spectra of the hot plasma source can be minimized through using high resolution spectrometers or using an alternative analyte line. The background effects need the use of offline background correction techniques, or through moving to an unaffected analyte line. The matrix effects are commonly handled by using internal standard method.
• The ICP spectrometers are, therefore, relatively expensive to purchase and difficult to operate as the user requires extensive training for the maintenance of the instrument.