Improving analytical precision by utilizing intrinsic internal standards for determining minor constituents by inductively coupled plasma atomic emission spectrometry

Abstract

In order to improve analytical precision, intrinsic internal standardization was applied to two routine analyses. Matrix emission lines that closely matched the noise patterns of the emission lines of the analytes were chosen. These noise patterns were induced by varying the ICP rf power and argon carrier flow rate. The changes in these two experimental conditions affect the plasma temperature, amount of aerosol injected into the plasma and analyte residence time in the plasma. Consequently, they contribute significantly to the over-all variability. Two lighting materials were chosen for this study: potassium-doped tungsten powder and europium-activated Y₂O₂S powder. Experimental results showed that with the intrinsic internal standard lines, the precision for determining the minor constituents (potassium in tungsten powder and iron in Y₂O₂S powder) was improved by 25–50%.