Inductively coupled plasma discharge

This is the basic process in an inductively coupled plasma discharge (ICP). The excited ions can be examined by observing the emitted light or by mass spectrometry. Since the molecules have been broken down into their constituent atoms (as ions) including isotopes, these can be identified and quantified by mass spectrometry, as happens with isotope ratio measurements. 

A. Gaillat, R.M. Barnes, P. Proulx, M.I. Boulos, Computer modelling of enclosed inductively coupled plasma discharges, Spectrochim. Acta B-At. Spectrosc. 50 (10) (1995) 1187-1205. 

Barnes R. M. and Nikdel S. (1976) Temperature and velocity profiles and energy balances for an inductively coupled plasma discharge in nitrogen, J Appl Phys 47 3929-3934. 

A number of electrical excitation-sources are available for emission spectroscopy. In most commercial spectrochemical instruments, more than one excitation source is contained in a single power-supply cabinet a typical combination may include a spark, a direct-current arc, and an alternating-current arc. A list of the various electrical excitation-sources, some of their characteristics, their approximate cost and the types of samples generally required is given in Table 11.1. Because of the actual or potential widespread use in emission spectroscopy, only the arc, spark, and inductively coupled plasma discharges will be described here in detail. 

Inductively Coupled Plasma Discharge An electrodeless radiofrequency discharge produced by magnetically induced eddy currents in flowing argon confined in a quartz tube at atmospheric pressure. liquids, powders, gases 6000-10,000... 

Figure 11.6. Schematic representation of an inductively coupled plasma discharge. Adapted from V. A. Fassel and R. N. Kniseley, Anal. Chem., 46, lllOA (1974), by permission of the publisher. Copyright 1974 by the American Chemical Society. 

The inductively coupled plasma [19] is excited by an electric field which is generated by an RF current in an inductor. The changing magnetic field of this inductor induces an electric field in which tire plasma electrons are accelerated. The helicon discharge [20] is a special type of inductively coupled RF discharge. 

ICP-MS Inductively coupled plasma Argon plasma discharge... 

There is a branch of MS specially designed for dealing with the analysis of inorganic materials.[21,22] Different specific ionization techniques, such as inductively coupled plasma mass spectrometry (ICP-MS),[23] glow discharge mass spectrometry (GD-MS)[24] and secondary ion mass spectrometry (SIMS),[25] are available and they are widely used in cultural heritage applications. Their description is beyond the scope of this chapter. 

Glow discharge source (GDMS) Laser ion source (LIMS) Secondary ion source (SIMS) Sputtered neutral source (SNMS) Thermal ionization source (TIMS) Inductively coupled plasma ion source (ICP-MS)... 

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). 

Recently, Hieftje et al.15-16 equipped a small double-focusing mass spectrograph built in house with Mattauch-Herzog geometry with several ion sources (such as glow discharge, an inductively coupled plasma ion source or a microwave plasma torch) and a novel array detector for simultaneous ion detection. 

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