Spark source mass metals

Qualitatively, the spark source mass spectrum is relatively simple and easy to interpret. Most instrumentation has been designed to operate with a mass resolution Al/dM of about 1500. For example, at mass M= 60 a difference of 0.04 amu can be resolved. This is sufficient for the separation of most hydrocarbons from metals of the same nominal mass and for precise mass determinations to identify most species. Each exposure, as described earlier and shown in Figure 2, covers the mass range from Be to U, with the elemental isotopic patterns clearly resolved for positive identification. 

Applications Real applications of spark-source MS started on an empirical basis before fundamental insights were available. SSMS is now considered obsolete in many areas, but various unique applications for a variety of biological substances and metals are reported. Usually, each application requires specific sample preparation, sparking procedure and ion detection. SSMS is now used only in a few laboratories worldwide. Spark-source mass spectrometry is still attractive for certain applications (e.g. in the microelectronics industry). This is especially so when a multi-element survey analysis is required, for which the accuracy of the technique is sufficient (generally 15-30% with calibration or within an order of magnitude without). SSMS is considered to be a... 

Table 5.6 compares the ICP-AES results with data generated for the same sample by two other independent methods - isotope dilution spark source mass spectrometry (IDSSMS), and graphite furnace atomic absorption spectrometry (GFAAS). The IDSSMS method also uses 25-fold preconcentration of the metals and matrix separation using the ion exchange procedure, following isotope... 

Heavy Metals, Isotope Dilution, Spark Source Mass Spectrometry, and Inductively Coupled Plasma Atomic Emission Spectrometry... 

A logical approach which serves to minimise such uncertainties is the use of a number of distinctly different analytical methods for the determination of each analyte wherein none of the methods would be expected to suffer identical interferences. In this manner, any correspondence observed between the results of different methods implies that a reliable estimate of the true value for the analyte concentration in the sample has been obtained. To this end Sturgeon et al. [21] carried out the analysis of coastal seawater for the above elements using isotope dilution spark source mass spectrometry. GFA-AS, and ICP-ES following trace metal separation-preconcentration (using ion exchange and chelation-solvent extraction), and direct analysis by GFA-AS. These workers discuss analytical advantages inherent in such an approach. 

Actinide metal samples are characterized by chemical and structure analysis. Multielement analysis by spark source mass spectrometry (SSMS) or inductively coupled argon plasma (ICAP) emission spectroscopy have lowered the detection limit for metallic impurities by 10 within the last two decades. The analysis of O, N, H by vacuum fusion requires large sample, but does not distinguish between bulk and surface of the material. Advanced techniques for surface analysis are being adapted for investigation of radioactive samples (Fig. 11) ... 

Carbide cluster ions (MC + - M = matrix element) have been measured by investigating them directly from the solid carbides (B4C,46 SiC) or by analyzing metal oxide/graphite mixtures (for M = rare earth element,3 Si,46 Th or U36). Figure 9.60 shows the distribution of silicon carbide cluster ions (SiC +) in laser ionization mass spectrometry by the direct analysis of compact SiC in comparison to the carbide cluster ion distribution of LaC + and SrC + in spark source mass spectrometry, by investigating a metal oxide/graphite mixture. 

Spark Source Mass Spectrometry. Another method for trace analysis probably should be mentioned and that is spark source mass spectrometry. In this technique, the sample in the form of a solid serves as an electrode and vapors, formed by sparking, are atomized and ionized to metal ions which are separated by a mass spectrometer and measured. The equipment is expensive and good results require the attention of a skilled operator. Even under the best conditions order of magnitude agreement of results is about the best that can be achieved. 

A nalysis of metal artifacts has long been a major tool in archaeological studies. Since by their very nature metal samples are electrically conducting, they are also well suited for analysis by spark source mass spectroscopy (SSMS). For several years we investigated the use of this technique and have applied it to archaeologically interesting samples. 

Although platinum was introduced to Europe in the mid-18th century, it was first made commercially available in large quantities and in malleable form in 1805 by the English chemist William Hyde Wollaston. Previous attempts at consistently producing malleable metal were hindered by chemical purification techniques that gave platinum contaminated with deleterious metallic impurities. Richard KnighPs improved process of 1800 was carried out on a suitable sample of crude ore, and analysis of the purified platinum by spark source mass spectrometry (SSMS) indicates an impurity level of about 6%. Reconstruction of Wollaston s purification procedures, coupled with SSMS analysis, indicates that his product was over 98% pure. His superior chemical purification techniques, coupled with improvements in the powder consolidation method, explain Wollastons success. 

Tt may be safe to say that the interest of environmental scientists in airborne metals closely parallels our ability to measure these components. Before the advent of atomic absorption spectroscopy, the metal content of environmental samples was analyzed predominantly by wet or classical chemical methods and by optical emission spectroscopy in the larger analytical laboratories. Since the introduction of atomic absorption techniques in the late 1950s and the increased application of x-ray fluorescence analysis, airborne metals have been more easily and more accurately characterized at trace levels than previously possible by the older techniques. These analytical methods along with other modem techniques such as spark source mass spectrometry and activation analysis... 

The role of Spark Source Mass Spectrography (SSMS) as a high sensitivity trace element analytical method is discussed. The unparalleled combination of sensitivity and complete element coverage makes SSMS especially suitable for the analysis of liquid and solid materials involved in semiconductor processing. Sample requirements are discussed. The application of SSMS to semiconductor materials, process reagents, dopants, and metals, is Illustrated. Advantages and disadvantages of the technique as well as sensitivity and accuracy are discussed. 

Spark source mass spectrography is the most useful tool available to the microelectronics industiry for bulk trace level impurity analyses of a wide variety of materials. The technique routinely examines ciTTstal growth start materials, crucibles, finished crystals, dopants, solvents, metals and all substances used in microelectronics manufacture. 

X-ray fluorescence spectroscopy has been used to determine 50 ppb of nickel and vanadium after they have been concentrated on ion exchange resins (5, 6). Emission spectroscopy has been used but is only semi-quantitative at the nanogram/gram levels of interest to the Project. Nevertheless, the technique may be useful as a screening tool. Two relatively new instrumental techniques—spark source mass spectrometry (7) and kinetics of metal-catalyzed reactions (8)—can measure extremely low levels of nickel and vanadium, but they have not been utilized to any appreciable extent. 

Uee am (1988b) Spark source mass spectrometry for the analysis of natural waters. In Butler LRP and Strasheim A, section editors. Atomic-, mass-, X-ray-spectrometric methods, electron paramagnetic and luminescence methods. In West TS and Niirnberg HW, eds. The determination of trace metals in natural waters. Section 2, pp. 105-108. Blackwell Scientific Publications, Oxford. 

Of course, the electron-impact source cannot be used if nonvolatile inorganic samples such as metal alloys or ionic residues are to be analyzed. These substances can be investigated using a different kind of ionization chamber called a spark source, similar to the excitation sources used in emission spectroscopy (Chap. 11). The other parts of the spectrometer can be the same as a general-purpose instrument however, a Mattauch-Herzog double-focusing instrument is preferred (Fig. 16.7 below), because the spark source produces ions with a wide spread of kinetic energies. The entire device is known as a spark-source mass spectrometer (SSMS). 

Despite these warnings of Craddock, which also apply to other mined and smelted metals like silver and iron, there have been serious attempts to glean locational information from analytical data. Berthoud, in his thesis research and in a paper published with several collaborators using plasma emission and spark source mass spectroscopy, analyzed the multivariate compositional data of copper ores from more than 25 copper mines in Iran, that would have been important in early (4th and 3rd millennium) metallurgy. Their feeling was that the Craddock Assumption 1) was satisfied well enough and furthermore that it was possible to trace certain 4th millennium objects from Susa to a native copper source at Talmessi. Of course, with native copper, Craddock Assumptions 2) and 3) were not tested. 

Table 4. Concentrations of some metals in animal blood determined by spark source mass spectrometry. Comparison of the concentration ranges of some elements obtain by the International Atomic Energy Agency (IAEA) with values from mammalian animal blood as reported by the United Kingdom Atomic Energy Commission (UKAEC) ...

In most analytical procedures, calibration is carried out by means of a calibration curve using com-pound(s) prepared with chemicals of an appropriate purity and verified stoichiometry. Matrix effects must often be taken into account and, consequently, the calibration solutions should be matrix-matched. CRMs of pure compounds may be used for calibration. However, matrix CRMs should in principle not be used for the purpose of calibration unless no other suitable calibrants are available, with the exception of those methods (e.g., spark source mass spectrometry, wavelength-dispersive XRF, etc.) that require calibration with CRMs of a similar, fully characterized matrix (e.g., metal alloys, cements). For such methods, accuracy can only be achieved when certified RMs are used for the calibration. 

Guthrie, J.W., 1964b, SC-TM-64-938. Analysis of Lutetium Metal by Spark Source Mass Spectroscopy. 

These limited quantities of californium metal place restrictions on the amount of analytical data that can be obtained for the products normally, analyses for hydrogen, nitrogen, and oxygen contents are not performed. The quality of the metal products has been determined by spark-source mass spectrometry, x-ray diffraction analysis, physical properties, appearance, and behavior in an experiment (such as the rate and extent of dissolution for heat-of-solution measurements). 

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