A Controlled-Atmosphere Plasma Arc for Emission Spectrography of Nonmetal Elements

Abstract

To estimate the weight percents of certain nonmetal elements in organic compounds found in petroleum reservoirs, the Bureau of Mines designed and constructed a controlled-atmosphere plasma arc which effectively excludes air from the plasma. Selected organic compounds that contained nonmetal elements were mixed with a solvent essentially free of those elements. The weight percents of the nonmetal elements were estimated from the produced diatomic spectral bands; results were reasonably accurate. Analytical working curves were prepared for nitrogen in the range from 15 to 450 µg for 100 mg samples using the analytical carbon-nitrogen band at 3883 Å and the internal standard carbon-carbon band at 3607 Å. Curves also were prepared for hydrogen, sulfur, and oxygen that had limited sensitivity to detection. Another indicated application of this plasma arc is for characterization of high-boiling petroleum fractions in liquid chromatographic effluents. The rates at which diatomic species are produced and destroyed directly influence the intensity of each corresponding band spectrum.

Analytical reactions involved in the spectrophotometric determination of alkylaluminum compounds using isoquinoline

“…A spectroscopic source which has shown ability to eliminate difficult matrices is the dc arc plasma jet (7)(8)(9)(10)(11)(12)(13)(14)(15)(16). The plasma jet typically operates in the 7000-10,000 °K temperature range and is designed so liquid samples can be introduced directly into the high energy dc arc.…”

Spatially resolved laser-induced fluorescence studies on a three-electrode direct current plasma

“…Elliott [9] described a device, similar to Owen's gas stabilized arc [7], which was offered commercially as the Spectrametrics, Inc. SpectraJet, shown in Figure 3. Several studies on this and similar designs soon followed [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. These included characterization and optimization of the operating parameters [9][10][11][12][13][14][15][16][17][18], and application studies [19][20][21][22][23][24][25].…”

“…Several studies on this and similar designs soon followed [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. These included characterization and optimization of the operating parameters [9][10][11][12][13][14][15][16][17][18], and application studies [19][20][21][22][23][24][25].…”

Wear metal determination by plasma jet direct current arc spectrometry

“…A spectroscopic source which has shown ability to eliminate difficult matrices is the dc arc plasma jet (7)(8)(9)(10)(11)(12)(13)(14)(15)(16). The plasma jet typically operates in the 7000-10,000 °K temperature range and is designed so liquid samples can be introduced directly into the high energy dc arc.…”