Spark source applications

H. Kramer, S. Semel J.E. Abel, Trace Elemental Survey Analysis of Trinitrotoluene , PATR 4767 (1975) (An evaluation of the applicability of spark source mass spectrometry and thermal neutron activation for the detn of origin-related trace elemental impurities in TNT) 10) C. Ribando J. Haber-man, Origin-Identification of Explosives Via Their Composite Impurity Profiles I. The... 

Applications Atomic emission spectrometry has been used for polymer/additive analysis in various forms, such as flame emission spectrometry (Section 8.3.2.1), spark source spectrometry (Section 8.3.2.2), GD-AES (Section 8.3.2.3), ICP-AES (Section 8.3.2.4), MIP-AES (Section 8.3.2.6) and LIBS. Only ICP-AES applications are significant. In hyphenated form, the use of element-specific detectors in GC-AED (Section 4.2) and PyGC-AED deserves mentioning. 

Applications Spark-source atomic emission and mass spectrometry have been used for routine analysis of solids, particularly for quality assurance and comparative work. As with GD-MS, spark sources are restricted to samples that are, to some extent, electrically conducting, or that can be made conducting by... 

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... 

The thermal ion mass spectrometer was specifically developed for the measurement of isotope abundances and is capable of excellent precision. Although the spark source mass spectrometer used in this work lacks some of this precision, it has proved very useful in stable isotope dilution work. It has a number of advantages, including greater versatility, relatively uniform sensitivity, and better applicability to a wide range of elements. 

A rather specialized emission source, which is applicable to the study of small samples or localized areas on a larger one, is the laser microprobe. A pulsed ruby laser beam is focused onto the surface of the sample to produce a signal from a localized area ca. 50 pm in diameter. The spectrum produced is similar to that produced by arc/spark sources and is processed by similar optical systems. 

G. Hungerford, The application of spark source fluorescence lifetime spectroscopy to the study of infrared fluorescence, transient species and DCM, Ph.D. thesis. University of Strathclyde, Glasgow, Scotland (1991). 

The eventual application towards which this work is progressing is biomedical mass spectrometry in the form of sophisticated research instruments and, ultimately, a fully automated "Clinical Mass Spectrometer" (22). This instrument will be capable of carrying out sophisticated analyses of physiological fluids and tissue in as routine a fashion in the clinical laboratory as conventional automated wet chemical procedure are employed today. In addition, many other applications of mass spectrometry are expected to benefit from the development of the EOID, e.g., spark source mass spectrometry, of mass spectrometers in spacecraft and on the surface of the planets, etc. 

As mentioned, thermal ionization mass spectrometry is the area in which isotope dilution developed and in which it has received the widest range of applications. One of thermal ionization s major limitations is that it is essentially a single-element technique in no way can it be considered multielement in the sense that numerous elements can be assayed in a single analysis. It is thus highly desirable to mate isotope dilution with multielement analysis capability. Spark source mass spectrometry for years dominated elemental analysis, but the nature of the samples (solids) made use of isotope dilution difficult. Use of a multielement spike was reported as long ago as 1970 by Paulsen et al. [17], however, and more recently by Carter et al. [18] and by Jochum et al. [19,20]. 

In the last decade or two, the advent of new instrumentation directed at elemental analysis has provided fertile new ground for expanded use of isotope dilution. Glow discharge mass spectrometry is in many ways the modem replacement for spark source and has similar impediments to ready application of isotope dilution. A recent report of Barshick et al. describes assaying lead in oil residues using the technique [21]. The obstacles spark source and glow discharge mass spectrometry both present to ready use of isotope dilution make it unlikely that widespread application of the technique will occur in conjunction with them. 

While high sensitivity has been obtained in the examination of pure materials, a far more rigorous test of the activation method is found in its application to materials of a more complex matrix. Emission and X-ray spectrometry and direct spark source mass spectrometry are all restricted by the lack of suitable standards when applied to materials of complex composition. Provided that precautions are taken to avoid self-shielding errors radioactivation is largely independent of the nature of the matrix material. It is this advantage which has enabled activation analysis to prove such an invaluable tool in geochemistry. 

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... 

Bacon J. R. and Ure A. (1984) Spark source mass spectrometry recent developments and applications, Analyst 109 1229-1254. 

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. 

The ideal situation for a process analyzer is to have the detector/electrical components in an area physically isolated from the sample stream and any liquid components required for calibration or instrument operation (e.g., solvents for liquid chromatography or gel-permeation chromatography). In this arrangement, isolation of the electrical components ensures that a spark source or hot surface (such as a spectroscopic light source) will not cause a problem with flammable components (both sample stream components and solvents). Also, this isolation wiU limit instrument damage in case of a sample system leak or solvent leak. Although the ideal situation is often not realized in a practical application, one should make every effort to protect the delicate sections of the instrument. In one application of the authors, a fiber optic probe having a quartz window sealed on the end of the probe was installed in the reactor of a process that contained... 

Another technique used for ionization of elements for MS determination is the spark-source technique (SS-MS), which presupposes solid sample preparations. A recent application of this technique on biological samples was described by Moody and Paulsen (1988). To avoid spectral interferences from organic ions, the samples were burnt in an oxygen stream. Mercury was collected in a liquid nitrogen trap, dissolved and coprecipitated with Ag as sulfide. The detection limit was probably in the range 10-100 g/kg dry matter. 

This chapter deals with optical atomic, emission spectrometry (AES). Generally, the atomizers listed in Table 8-1 not only convert the component of samples to atoms or elementary ions but, in the process, excite a fraction of these species to higher electronic stales.. 4, the excited species rapidly relax back to lower states, ultraviolet and visible line spectra arise that are useful for qualitative ant quantitative elemental analysis. Plasma sources have become, the most important and most widely used sources for AES. These devices, including the popular inductively coupled plasma source, are discussedfirst in this chapter. Then, emission spectroscopy based on electric arc and electric spark atomization and excitation is described. Historically, arc and spark sources were quite important in emission spectrometry, and they still have important applications for the determination of some metallic elements. Finally several miscellaneous atomic emission source.s, including jlanies, glow discharges, and lasers are presented. 

Applications of Spark Source Spectroscopy Quantitative spark analyses demand precise control of (he many variables involved in sample preparation and excitation. In addition, quantitative measurements require a set of carefully prepared standards for calibration these standards should approximate as closely as possible the composition and physical properties of the samples to be analyzed, (iencrally, spark source analyses are based on the ratio of intensity of the analyte line to the intensity of an internal-standard line (usually a line of a major consliluciil >f the sample). Under ideal conditions, relative standard deviations of a few percent can be achieved with spark spectral measurements. 

Table 11 -1 lists the most important typos of atomic mass spectromelry. Hislorically, thermal ionization mass spectrometry and spark. source mass spectrometry were the lirsl mass spectromdric methods developed for qualiialive and quantitative elemenlul analysis, and these types of procedures still Had applications, although they are now overshadowed by some of (he other methods listed in Table 11-1, particularly indue lively coupled plasma mass spectrometry (1((PMS),... 

As mentioned previously, mass spectrometry can be applied to nonvolatile inorganic substances by using a spark source. One important analytical application is the... 

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