Helium microwave glow discharge

More recent work on the determination of alkylmercury compounds has been centred on the applicability of the helium microwave glow discharge detector as a gas chromatographic detector. This has been discussed by Bache and Lisk. Grossman, Talmi92 and Quimby et al have examined the applicability of helium microwave glow discharge detectors to the detection of diphenylmercury. 

Various workers (Reamer et al, and Quimby et al ) have examined the applicability of helium in microwave glow discharge detectors for the detection of organolead compounds leaving a gas chromatographic column. A microwave emission detector (MED) was firsi described by McCormack et al. ... 

Poljraer surfaces can be easily modified with microwave or radio-frequency-energized glow discharge techniques. The polymer surface cross-links or oxidizes, depending on the nature of the plasma atmosphere. Oxidizing (oxygen) and nonoxidizing (helium) plasmas can have a wide variety of effects on polymer surface wettability characteristics (92). 

Amano succeeded in observing the lowest rotational transition of the CH radical, generated by means of a glow discharge in mixture of CH4 and helium. The observation of this spectrum is a major achievement in microwave spectroscopy we show a part of the spectrum in figure 10.31, exhibiting two proton hyperfine lines, but defer a detailed discussion of the energy levels and spectrum until later in this chapter. 

Common gas chromatographic detectors that are not element- or metal-specific, atomic absorption and atomic emission detectors that are element-specific, and mass spectrometric detectors have all been used with the hydride systems. Flame atomic absorption and emission spectrometers do not have sufficiently low detection limits to be useful for trace element work. Atomic fluorescence [37] and molecular flame emission [38-40] were used by a few investigators only. The most frequently employed detectors are based on microwave-induced plasma emission, helium glow discharges, and quartz tube atomizers with atomic absorption spectrometers. A review of such systems as applied to the determination of arsenic, associated with an extensive bibliography, is available in the literature [36]. In addition, a continuous hydride generation system was coupled to a direct-current plasma emission spectrometer for the determination of arsenite, arsenate, and total arsenic in water and tuna fish samples [41]. 

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