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Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials

Circular 591

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Abstract

Two spectrographic methods are used in mobile field laboratories of the U. S. Geological Survey. In the direct-current arc method, the ground sample is mixed with graphite powder, packed into an electrode crater, and burned to completion. Thirty elements are determined. In the spark method, the sample, ground to pass a 150-mesh screen, is digested in hydrofluoric acid followed by evaporation to dryness and dissolution in aqua regia. The solution is fed into the spark gap by means of a rotating-disk electrode arrangement and is excited with an alternating-current spark discharge. Fourteen elements are determined. In both techniques, light is recorded on Spectrum Analysis No. 1, 35-millimeter film, and the spectra are compared visually with those of standard films.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials
Series title:
Circular
Series number:
591
Edition:
-
Year Published:
1968
Language:
ENGLISH
Publisher:
[U.S. Geological Survey],
Description:
iii, 6 p. :illus. ;26 cm.