Ionization interference is more common in hot flames. The dissociation process does not stop at formation of ground state atoms. Excess energy of the flame can lead to excitation of ground state atoms to ionic state by loss of electrons thereby resulting in depletion of ground state atoms. In cooler flames such interference is encountered with easily ionized elements such as alkali metals and alkaline earths.
Ionisation interference is eliminated by adding an excess of an element which is easily ionized thereby creating a large number of free electrons in the flame and suppressing ionization of the analyte. Salts of such elements as K, Rb and Cs are commonly used as ionization suppressants.