ICP - Nebuliser

Nebulizers perform the function of converting liquid samples to an aerosol, consisting of finely divided droplets, which are suspended in the plasma carrier gas. This aerosol, which is presumably representative of the composition of the original sample, is transported to the plasma torch, where it is injected into the central channel of the plasma for subsequent atomization and ionization.

The liquid aerosol is introduced into the "thermal front" at the base of the plasma, the solvent is evaporated when the temperature of the aerosol reaches the solvent s boiling point.

The resulting "dry aerosol" continues to be transported into a higher temperature region of the plasma. When the melting point, followed by the decomposition temperature of the residue is reached, simple molecules and atoms are formed.

Finally, in the highest temperature region of the plasma, complete atomization occurs, and the resulting atoms are efficiently ionized prior to being sampled by the mass spectrometer interface and transported to the UV - Visible Spectrophotometer / mass spectrophotometer for analysis. In addition, molecules formed from the decomposition of the dry aerosol or recombination by collisions of the atoms can form ions also.
The aerosol formed by the nebulization process creates a population of droplets that have a distribution of sizes, ranging from a mean diameter of about 1 to 80 Micron.

The more uniform the droplet size (i.e., the narrower the size distribution) the more precise the results of the subsequent analytical determinations.

Larger droplets require more energy to evaporate the solvent and subsequently more energy to vaporize and atomize the post solvent removal residue, resulting in local instability in the plasma.

This instability is reflected in the measured ion currents of the analyte elements.