Spark-source mass spectrometer

Spark Source Mass Spectrometry (SSMS) is a method of trace level analysis—less than 1 part per million atomic (ppma)—in which a solid material, in the form of two conducting electrodes, is vaporized and ionized by a high-voltage radio frequency spark in vacuum. The ions produced from the sample electrodes are accelerated into a mass spectrometer, separated according to their mass-to-charge ratio, and collected for qualitative identification and quantitative analysis. 

Figure 1 Schematic diagram of a Mattauch-Herzog geometry spark source mass spectrometer using an ion-sensitive plate detector.

The earlier stable isotope dilution mass spectrographic work was accomplished with a thermal ion mass spectrometer which had been specifically designed for isotope abundance measurements. However, Leipziger [829] demonstrated that the spark source mass spectrometer could also be used satisfactorily for this purpose. Although it did not possess the excellent precision of the thermal unit, Paulsen and coworkers [830] pointed out that it did have a number of important advantages. 

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. 

The ion source is an essential component of all mass spectrometers where the ionization of a gaseous, liquid or solid sample takes place. In inorganic mass spectrometry, several ion sources, based on different evaporation and ionization processes, such as spark ion source, glow discharge ion source, laser ion source (non-resonant and resonant), secondary ion source, sputtered neutral ion source and inductively coupled plasma ion source, have been employed for a multitude of quite different application fields (see Chapter 9). 

The glow discharge ion source is simple yet versatile, providing information for emission and mass spectrometric methods.92 A glow discharge ion source combined with a mass spectrometer has supplanted the spark ion source over many decades as the predominant ionization technique of mass spectrometry for determining trace and ultratrace element concentrations in various types of... 

In 1977, Jochum et aZ.12,14 developed the multiple ion counting (MC) technique using an old spark source mass spectrometer with 20 separate channeltrons 1.8 mm wide for simultaneous electrical ion detection. The sensitivity was increased by a factor of 20 compared to SSMS with ion detection using a photoplate and the precision of the analytical results was improved. 

Figure 5.24 Experimental setup of a double-focusing sector field mass spectrometer with Mattauch-Herzog geometry with interchangeable spark and laser ion source. (/. 5. Becker and H. /. Dietze, Int. /. Mass Spectrom. Ion Proc. 197, 1 (2000). Reproduced by permission of Elsevier.)...

SSMS - spark source mass spectrometer Mattauch-Herzog geometry ( / 10000). 

While our research was concerned with developing wet chemical methods, we confirmed our data with analyses from an available spark source mass spectrometer (SSMS). The SSMS operating parameters are given in Table I. The instrument used was an AEI MS-7 (I, 2) equipped with electrical detection. It was used in the peak switching mode only to provide more precise analyses. 

Instrumentation. The instrument used in this investigation was a commercial Mattauch-Herzog mass spectrometer equipped with photographic and electrical detection systems and an RF spark source. The resolution of the instrument was 1 part in 5,000. All trace elements were determined from mass spectra recorded on Ilford Q-2 photographic... 

Figure 1. Schematic diagram of a double focusing spark source mass spectrometer...

Isotope Dilution By Spark Source Mass Spectrometry. A unique and quite different approach to determining trace elements in solids, liquids, and gases uses the isotope dilution technique. This method has been operational for some time with mass spectrometers. Thermal ionization... 

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. 

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. 

In 1965 Long published a proposed ion microprobe analyzer [27]. Long s student, Drummond, began construction and in 1967 published secondary electron micrographs showing 0.5-pm resolution [28] using a primary beam column. This became the basis for the Associated Electrical Industries (AEI) Ltd. SIMS instrument [29]. This instrument utilized AEI s MS702R spark source mass spectrometer for secondary ion analysis and had a mass resolution of -5000. 

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