Suppression of Cyanogen Bands for the Spectrographic Analysis of Erbium Oxide

The suppression of cyanogen bands from direct current arc spectra by using atmospheres of argon, helium, and carbon dioxide, and binary mixtures of these gases with oxygen has been investigated. Analytical working curves for the determination of dysprosium, thulium, and holmium in erbium oxide have been prepared from spectra of samples arced in an atmosphere of 80% argon – 20% oxygen. Cyanogen bands were eliminated to permit the use of sensitive lines in these regions; background intensity was also reduced.