The experience of the author and others with the <i>evaporation method</i> is described. The technique consists of evaporating trace amounts of impurities from the molten sample in an electrically heated crucible and condensing them on a water-cooled electrode, which is then arced or sparked. Temperatures used range from 1500 to 2000°C and element sensitivities from 20 to 0.02 ppm.
S. Mandelstam, "Spectrochemical Analysis by the Evaporation Method," Appl. Spectrosc. 11, 157-158 (1957)