Plasma and Its Characteristics:

An ideal atomization-excitation source shall have the following characteristics.

1. It should completely separate the analyte from its original matrix so as to minimise interferences.

2. It should have appropriate energy to ensure complete atomisation but keep ionisation to a minimum.

3. It should provide an inert environment, so as to remain the undesirable molecular species creation to a minimum.

4. It should have none or negligible background radiation.

5. It should provide for the analysis of samples in all possible forms like, solids, liquids, gases or slurries.

6. Of course, it should be inexpensive, required minimal maintenance and be easy to operate.

As always, it is difficult to attain ideality, however, plasma sources are quite promising for the purpose of atomisation-excitation job in atomic emission spectrometry. You have learnt above in which a plasma source is an electrically neutral, highly ionised gas that consists of ions and electrons. It is sustained by absorbing energy from an electric or magnetic field. Three types of power sources have been employed in argon plasma spectroscopy. One is a powerful radio frequency generator that powers an induction coil, a magnetic field produced from it help in build the plasma. Another is a dc electrical source capable of managing a current of several amperes between electrodes immersed in the argon plasma and third one is a microwave frequency generator through which the argon flows.