Plasma sources Inductively coupled plasmas

Plasma source, inductively coupled plasma (ICP) A plasma source where the plasma is formed in a region surrounded by an rf coil that couples energy into the electrons in the plasma. 

ASIA atomizer, source, inductively coupled plasma in atomic fluorescence... 

As described previously, vapour introduction approaches are by far the most common application of atomic fluorescence. Despite this, mention of other methods should be made. If a conventional nebulizer and spray chamber assembly (see AAS section) is used, it is possible to introduce liquid samples directly to the atom cell. In circumstances such as these, it is necessary to use more robust air-acetylene or nitrous oxide-acetylene flame, or perhaps an ICP. The use of an ICP as an atom cell for AFS measurements has led to the development of a number of different techniques, e.g. ASIA, an acronym for atomiser, source, inductively coupled plasmas in AFS. This technique uses a high-powered ICP as a source and a low-powered ICP for the atom cell. It has been found that ICP-AFS yields linear calibrations over 4—6 orders of magnitude and is more sensitive than ICP-AES. 

Spectroscopic methods for the deterrnination of impurities in niobium include the older arc and spark emission procedures (53) along with newer inductively coupled plasma source optical emission methods (54). Some work has been done using inductively coupled mass spectroscopy to determine impurities in niobium (55,56). X-ray fluorescence analysis, a widely used method for niobium analysis, is used for routine work by niobium concentrates producers (57,58). Paying careful attention to matrix effects, precision and accuracy of x-ray fluorescence analyses are at least equal to those of the gravimetric and ion-exchange methods. 

The Inductively Coupled Plasma (ICP) has become the most popular source for multielement analysis via optical spectroscopy since the introduction of the first commercial instruments in 1974. About 6000 ICP-Optical Emission Spectrometry (ICP-OES) instruments are in operation throughout the world. 

The inductively coupled plasma source (Fig. 20.11) comprises three concentric silica quartz tubes, each of which is open at the top. The argon stream that carries the sample, in the form of an aerosol, passes through the central tube. The excitation is provided by two or three turns of a metal induction tube through which flows a radio-frequency current (frequency 27 MHz). The second gas flow of argon of rate between 10 and 15 L min-1 maintains the plasma. It is this gas stream that is excited by the radio-frequency power. The plasma gas flows in a helical pattern which provides stability and helps to isolate thermally the outside quartz tube. 

Inductively coupled plasma Plasmas generated by application of radiofrequency power to a nonresonant inductive coil and maintained by an inductive electromagnetic field. Low-pressure ICP is a high-density plasma source. 

Gray AL (1985). Solid sample introduction by laser ablation for inductively coupled plasma source mass spectrometry. Analyst 110 551-556... 

Delves HT, Campbell MJ. 1988. Measurements of total lead concentrations and of lead isotope ratios in whole blood by use of inductively coupled plasma source mass spectrometry. J Analytical Atomic Spectrometry 3 343-348. 

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

The outline of the construction of a typical plasma emission spectrometer is to be seen in Figure 8.10. The example shown has an inductively coupled plasma, excitation source, but the outline would be similar were a dc source to be fitted. Different combinations of prisms and diffraction gratings may be used in the dispersion of the emitted radiation, and in the presentation of the analytical signal. Instruments are computerized in operation and make use of automatic sample handling. Sophisticated data handling packages are employed routinely to deal with interferences, and to provide for clarity in data output. 

Inductively coupled plasma ICP Plasma source Atomic ions Isotope ratio Trace analysis... 

Figure 2.4. Schematic of an inductively coupled plasma (ICP) ion source.

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