Surfatron

Because MIPs are formed at low temperatures, liquid samples cannot be introduced because they extinguish the plasma, even small amounts of organic vapour. However, the on-line coupling of HPEC to MIP-OES has been described for the speciation of mercury and arsenic compounds. Continuous cold vapour (CV) or hydride generation (HG) techniques were used as interfaces between the exit of the HPEC column and the MIP, held in a surfatron at reduced pressure [24]. 

A surfatron microwave-induced plasma was reported for the selective detection of catechols after SFC separation of the compounds as cylic bo-ronate esters [39]. An available spectroscopic system was modified to utilize... 

Richts U., Broekaert J. A. C., Tschopel P. and Tolg G. (1991) Comparative study of a Beenakker cavity and a surfatron in combination with electrothermal evaporation from a tungsten coil for microwave plasma optical emission spectrometry (MIP-AES), Talanta 38 863-869. 

Before entering the fluidizing column, nitrogen underwent a 2.45 GHz microwave discharge by passing through a microwave cavity (surfatron). The fluidized bed was 25 cm downstream of the surfatron. The power was maintained at 300W. 

Plasma sources are capable of producing intense emission from the elements. Types of plasma used in chromatographic detection are microwave induced plasmas (MIP) and inductively coupled plasma (ICP). An argon plasma is sustained in a microwave cavity which focuses into a capillary discharge cell. The most widely used cavities are cyhndrical resonance cavities and surfatron that operates by surface microwave propagation along a plasma column. Atmospheric pressure cavities are very simple to interface with capillary GC columns. 

Luffer, D.R. Novotny, M. Element-selective detection after supercritical fluid chromatography by means of a Surfatron plasma in the near-infrared spectral region. J. Chromatogr. 1990, 517, 477 89. 

The MIP is also useful for the excitation of volatile hydride-forming elements after stripping the hydrides of the excess of hydrogen. With different trapping techniques, detection limits down to the sub-ng level can easily be obtained [177]. A further usefid type of MIP is the so[Pg.261]

Moussanda P. S., Ranson P. and Mermet j. M. (1985) Spatially resolved spectroscopic diagnostics of an argon MIP produced by surface wave propagation (Surfatron), Spectrochim. Acta, Part B 40 641-651. 

Another type of microwave plasma cavity which has been used successfully in GC-MIP is the Surfatron which operates by surface microwave propagation along a plasma column [17]. The plasma may be viewed axially or transversely since it extends outside the plasma structure it can sustain a dicharge over a wide pressure range. 

Although analytical SFC was demonstrated in the early 1960s, it has only been in recent years that the availability of adequate high resolution packed and capillary SFC columns and instrumentation has led to renewed interest in the technique. Plasma emission is a natural development because of its use in GC and HPLC. A surfatron MIP sustained in helium has been employed for SFC detection, giving sulfur-specific detection at 921.3 nm with a 25 pg s limit for thiophene [28]. An argon high efficiency MIP has been interfaced with packed column SFC and the separation and detection of ferrocene and derivatives achieved with iron specific detection. Methanol modifier concentrations to 5% were tolerated in the carbon dioxide mobile phase [29]. 

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