Spectrographic analysis of refractory magnesium oxide: A buffer approach

Abstract

A method has been described for the determination of eighteen trace elements in refractory magnesium oxide by optical emission spectroscopy. The main feature of the method is the use of a spectroscopic buffer instead of a carrier. When conducting graphite powder has been added as a buffer to the MgO sample prior to its excitation in a d.c. arc, there has been a smooth distillation of the matrix magnesium as well as the trace elements into the arc column. Addition of a carrier, however, does not either completely prevent the emission of Mg spectrum or result in smooth distillation. A Hilger large quartz spectrograph has been employed to record the spectra excited at 10 amp d.c. The Ga line at 265.99 nm has been used as an internal standard for the more volatile trace elements and the Mg line at 280.98 nm has been employed as an internal standard for the less volatile trace elements. The detection limits obtained range from 0.5–5 ppm for the various elements. The mean relative standard deviation (RSD) of the method is ± 14%.