Calculation of method evaluation functions for inductively coupled plasma atomic emission spectrometric analysis for iron, manganese and titanium from metal-spiked filter samples

Abstract

The method evaluating function (MEF) is defined as the expected value of the analysis as a function of the ‘true’ content of the analyte in the samples. The MEF describes the complete analytical range and contains most of the relevant information on a chemical analytical method. The calculation of the MEF provides an easy way to obtain stringent documentation on an analytical method. MEFs for the multi-element inductively coupled plasma atomic emission spectrometric (ICP-AES) determination of Fe, Mn and Ti have been established. Parameter estimators, based on the method of weighted least-squares regression, including confidence intervals for the zero-point error α and the slope of β of the regression curve, were determined. The overall analytical error, i.e., the day-to-day variation and the variation within a single run of the analysis were calculated. Certification limits were set, for use of the ICP-AES analysis in the development of interlaboratory control filters, based on the square root of the relative mean square error.