A rapid and accurate spectrochemical method is presented for the determination of ferric oxide and silicon dioxide in alumina. This method is much more convenient than time-consuming gravimetric methods in which fusions are necessary for dissolution of the sample. The spectrographic method employs the use of finely divided germanium metal and graphite powder as buffers. The addition of germanium yields uniform, reproducible spectral lines. Data on the reproducibility of intensity ratios are included.
Doris Conrad, "Spectrochemical Determination of Ferric Oxide and Silicon Dioxide in Alumina," Appl. Spectrosc. 11, 84-86 (1957)