Matrix Effects and Chemical Interferences

Matrix effects include nebulisation interference, transfer and desolvation interference, chemical or ionisation interference, and atomisation and volatilisation interference. Although the primary indication is a change in the emission intensity, it is often difficult to determine the origin of the interference. 

Due to the high gas temperature of the ICP, long residence times, and inert gas atmosphere, chemical interference from the formation of thermally stable compounds or radicals are rarely observed for ICP sources, with low power ICPs being the only exception. However, this interference is common in atomisation sources with low gas temperatures, for example the DCP, MIP, or flame. 

Easily ionisable elements, such as alkali and alkaline earth metal elements, can alter the emission intensity and may cause an enhancement or a depression. This problem is more serious with DCPs, MIPs, and CMPs, while less important with ICPs. Several mechanisms have been suggested to explain these changes, for example lateral diffusion, changes in thermal conductivity, an altered volatihsation rate, ambipolar diffusion, or shifts in the ionisation equilibrium and the collisional processes. 

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