A Hollow Cathode Source Applicable to Spectrographic Analysis for the Halogens and Gases*

Investigations aimed at developing methods of spectrographic quantitative analysis of the halogens and non-metals have been carried out, with emphasis on analysis for fluorine. The relative sensitivities of fluorine spectrum lines in the vacuum ultraviolet region and in the visible region were studied, and it was found that certain visible lines are, at present, more sensitive than the theoretical raies ultimes of fluorine. The greatest absolute sensitivity obtained, using a specially designed hollow cathode source, involved detection of about 0.01 microgram of fluorine, while the greatest concentrational sensitivity was slightly less than one part per million. Chlorine and sulphur were readily detected in amounts as small as 0.20 microgram and 1.0 microgram, respectively, in samples weighing 20 milligrams. Sample handling time was reduced sufficiently to permit routine analyses for these elements.