FLOW-INJECTION SAMPLE-TO-STANDARD ADDITIONS METHOD USING ATOMIC-ABSORPTION SPECTROMETRY APPLICABLE TO SLURRIES

An extension of the flow injection (Fl) sample-to-standard additions method using atomic absorption spectrometry for detection is discussed. Hypotheses are given for slurries injected into a simple Fl manifold, with a standard solution of the analyte used as the carrier. An equation is derived allowing the calculation of the concentration of the sample from two signals, one obtained from the injection of the slurried sample and the other from a slurry prepared from a standard of known concentration. The reliability of the approach is confirmed by determining the concentrations of copper, manganese, chromium and zinc in slurries prepared from commercial iron oxide pigments. The results show good precision (relative standard deviation of less than 3.8%) and accuracy (relative errors in the 0.6-5.8% range).