Ionization buffers are used for the suppression of physical, ionic, and chemical interferences for use with flame atomic absorption spectroscopy. These are buffers added to increase the free-electron concentration by the flame gases, thus repressing and stabilizing the degree of ionization. A fast universal calibration method was described by Schuhknecht and Schinkel, who recommended the addition of cesium chloride and aluminum nitrate to the samples and standard solutions in the flame emission spectroscopic determination of sodium, potassium, and lithium.