Vaporisation interference of sulphate and phosphate anions on the calcium flame atomic-absorption signal

The depressive effect of sulphate and phosphate anions on the calcium atomic-absorption signal was studied in an air-acetylene flame. During the solute nebulisation calcium sulphate and pyrophosphate aerosol particles are formed. The vaporisation of these particles will be the rate-determining step in the atom-formation process. It follows from this fact that no linear relation exists between the measured absorbance and the analyte concentration.