Application of the generalized internal reference method to high accuracy assay of metallurgical samples by ICP

Abstract

Determination of major constituents in metallurgical samples requires an accuracy of better than 1 %, which cannot be achieved by inductively coupled plasma (ICP). Use of a multivariable internal reference procedure, the generalized internal reference method (GIRM), to achieve this goal is examined. The adequacy of the GIRM was tested for low-alloy steels and aluminum alloys. Major, minor and trace elements were determined simultaneously on a direct reading spectrometer. A precision of 0.3–0.1 % with an accuracy of better than the certified range was achieved. Spectral lines of the major element and argon were used as internal reference and no internal reference element was added. Single point calibration was used to determine concentrations varying by up to two orders of magnitude.