Capacitively coupled microwave

Atsuya and Akatsuka [140] have described a method for determining trace amounts of arsenic. The technique, which uses capacitively coupled microwave plasma with an arsine generation system, has been used to determine arsenic in sewage sludge. 

The capacitatively coupled microwave plasma is formed by coupling a 2450 MHz magnetron, via a coaxial waveguide, to metal plates or a torch where the plasma is formed. Considerable problems have been encountered with this low-cost plasma, particularly from easily ionizable elements which cause dramatic changes in the excitation temperature in the plasma. 

Further designs of ion sources applied in plasma spectroscopy such as electrodeless microwave induced plasmas (MIPs) operating in a noble gas atmosphere at low power (mostly below 200 W) or capacitively coupled microwave plasma using Ar, He or N2 the as plasma gas (at 400-800 W) were described in detail by Broekaert.33 Microwave plasmas produced by a magnetron are operated at 1-5 GHz. Their special application fields for selected elements and/or element species are based (due to the low power applied) in atomic emission spectrometry.33... 

Kitagawa K, Nishimoto N. 1989. Thermal vaporizer - capacitively coupled microwave plasma system for trace mercury determination. J Spectrosc Soc Japan 38(4) 282-287. 

Fig. 103. Capacitively coupled microwave plasma (A) [442] and microwave induced plasma discharges (B, C). (B) MIP in a TMoio resonator according to Beenakker (a) cylindrical wall, (b) fixed bottom, (c) removable lid, (d) discharge tube, (e) holder, (f) coupling loop, (g) PTFE insulator, (h) ...

Seelig M., Bings N. H. and Broekaert J. A. C. (1998) Use of a capacitively coupled microwave plasma (CMP) with Ar, N2 and air as working gases for atomic spectrometric elemental determinations in aqueous solutions and oils, Fresenius ... 

The analytical plasmas are classified according to the method of power transmission to the working gas. There are three dominant types of plasma source in use today (i) Inductively coupled plasmas, ICPs (ii) Direct current plasmas, DCPs (current carrying DC plasmas and current-free DC plasmas) (iii) Microwave plasmas (microwave induced plasmas, MIPs, and capacitively coupled microwave plasmas, CMPs). 

A) Arc B) Spark C) Flame D) Plasma sources E) Low-pressure discharges F) Graphite furnace G) Laser plume ICP = Inductively coupled plasma DCP=Direct current plasmajet CMP = Capacitively-coupled microwave plasma MIP = Microwave-induced plasma GDL = Glow discharge lamp HC = Hollow cathode... 

Seelig M. and Broekaert J. A. C. (2000) Investigations on the on-line determination of metals in air flows by capacitively coupled microwave plasma atomic emission spectrometry (CMP-OES), Spectrochim. Acta, Part B in press. 

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