Spectrographic analysis

Ultrapure (triple distilled) mercury is commonly tested by evaporation or spectrographic analysis. In the former, a composite sample is evaporated and the residue weighed. In spectrographic analysis, a sample is dissolved and evaporated, the residue mixed with graphite [7782-42-5] and the emission spectmm determined with a spectrograph. 

Beryllium Oxalate. BeryUium oxalate trihydrate [15771 -43-4], BeC204 -3H20, is obtained by evaporating a solution of beryUium hydroxide or oxide carbonate in a slight excess of oxaHc acid. The compound is very soluble in water. Beryllium oxalate is important for the preparation of ultrapure beryllium hydroxide by thermal decomposition above 320°C. The latter is frequentiy used as a standard for spectrographic analysis of beryUium compounds. 

Close examination of the weld under a low-power stereoscopic microscope revealed small openings (Fig. 15.6). Probing these sites with a pin revealed a large pit that had been covered by a thin skin of weld metal. These sites contained fibrous, metallic remnants (Fig. 15.7). Examination under a scanning electron microscope further revealed the fibrous character of the material (Fig. 15.2) and also the convoluted shapes of the individual fibers (Fig. 15.21). Energy-dispersive spectrographic analysis of this material revealed the compositions in Table 15.1. 

Until recently, tribology analysis has been a relatively slow and expensive process. Analyses were conducted using traditional laboratory techniques and required extensive, skilled labor. Microprocessor-based systems are now available which can automate most of the lubricating oil and spectrographic analysis, thus reducing the manual effort and cost of analysis. 

Spectrographic analysis allows accurate, rapid measurements of many of the elements present in lubricating oil. These elements are generally classified as wear metals, contaminates, or additives. Some elements can be listed in more than one of these classifications. Standard lubricating oil analysis does not attempt to determine the specific failure modes of developing machine-train problems. Therefore, additional techniques must be used as part of a comprehensive predictive maintenance program. 

Normal spectrographic analysis is limited to particulate contamination with a size of 10 microns or less. Larger contaminants are ignored. This fact can limit the benefits that can be derived from the technique. 

The capital cost of spectrographic analysis instrumentation is normally too high to justify in-plant testing. Typical cost for a microprocessor-based spectrographic system is between 30,000 and 60,000. Because of this, most predictive maintenance programs rely on third party analysis of oil samples. 

Lubricating oil samples from all equipment included in the program should be taken on a monthly basis. As a minimum, a full spectrographic analysis should be conducted on these samples. Wear particle or other analysis techniques should be made on an as-needed basis. 

Chemical and catalytic. This grade of platinum is for conversion to catalysts, gauzes and chemical compounds. Spectrographic analysis is employed to control the presence of trace impurities harmful in these applications. 

Quality control tests are intended to detect produced materials which deviate from manufacturing specifications, and thus may result in questionable performance. The materials are usually subjected to spectrographic analysis which is the primary quality control check. The exposure tests are necessarily of short duration (hours or days), in which the test conditions attempt to reflect the environment of operation, for example using artificial seawater for a marine application. Since a property that is reproducible and indicative of a consistent quality anode is all that is required, there is no attempt to mirror, except in the crudest fashion, current density profiles. 

We may now deal with some of the procedures employed in quantitative spectrographic analysis. In the comparison sample method, the spectrum of an unknown sample is compared with the spectra of a range of samples of known composition (e.g. those supplied by the US Bureau of Standards) with respect to a particular component or components. The spectra of the unknown and of the various standards are photographed on the same plate under the same conditions. The concentrations of the desired constituent can then be estimated by comparing the blackening of the lines of the particular constituent with the same lines on the standards visual or photometric comparison of blackening may be used. 

QUALITATIVE SPECTROGRAPHIC ANALYSIS OF (A) A NON-FERROUS ALLOY AND (B) A COMPLEX INORGANIC MIXTURE... 

Specific absorption coefficient 650 Specific gravities solutions of acids, (T) 829 of selected reagents (T), 829 Spectral half bandwidth 663 Spectrofluorimetry 731 Spectrograph adjustment of, 771 commercial instruments, 761, 775, 776 Spectrographic analysis see Emission spectrographic analysis... 

Qualitative spectrographic analysis of (A) a non-ferrous alloy, and (B) a complex inorganic mixture 770... 

Rollefson, G. K. Dodgen, H. W. "Report on Spectrographic Analysis Work CK-812", July 1943 (Declassified 29 December 1954). 

The supposed human remains were accompanied by flint implements and animal teeth, all of which apparently supported the early date attributed to the find. The flint implements were of a reddish color, matching that of local flints, but spectrographic analysis revealed that they had been artificially stained with chromium and iron salts below the layer of stain there was a white crust, whereas local flints were brown throughout. The animal teeth also seemed to have been "planted" at the burial site so as to suggest an early date the red-brown color of the teeth had also been artificially stained chromium and iron had been found when they were analyzed. A hippopotamus tooth, previously supposed to be contemporary with the tool carved from the elephant s tusk, was also stained with chromium and iron salts and contained little fluorine. 

Harvey CE (1947) A method of semi-quantitative spectrographic analysis. A.R.L., Glendale, CA... 

Table VIII shows the results of a CH3—CH=CD2 isomerization run. Product analysis was carried out by IR and mass spectrographic analysis.

N. B. Hannay. Mass Spectrographic Analysis of Solids High Sensitivity for Bulk and Surface Impurities is Provided by a New Analytical Method. Science, 134(1961) 1220-1225. 

Brown, M. A. and Blin-Stoyle, A. E. (1959). Spectrographic analysis of British Middle and Late Bronze Age finds (including reprint of A sample analysis of British Middle and Late Bronze Age material, using optical spectrometry , from Proceedings of the Prehistoric Society.) Supplement to Archaeometry 2. 

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