Plasma generation

Steve J Hill Andy Fisher and Martin Liezers 

Inductively Coupled Plasma Mass Spectrometry Handbook Edited by Simon M. Nelms 2005 Blackwell Publishing Ltd. ISBN 978-1-405-10916-1 

The standard Fassel-style torch is 18 mm in diameter and the injector has a typical bore of 1.5 mm. There are torches that have smaller dimensions, lower gas flow rates and operate at a reduced power. It has been demonstrated that the figures of merit for these torches, in terms of limit of detection and precision, are only marginally inferior to those from the standard-size torch, but they are also less tolerant of samples with a high content of dissolved solids. For such samples, the injector becomes blocked relatively easily and will become unusable after only a few samples. Conversely, the low-flow torch is more capable of sustaining a plasma when organic solvents are introduced. 

For additional information regarding the various gases that have been used and the range of apphcations to which this approach has been applied, the interested reader is directed to reviews elsewhere. 

The argon ICP is by far the most common type of plasma to be coupled with mass spectrometric detection. As discussed above, alternative gas and mixed gas plasmas have been used, but several other types of plasma have also been employed one such plasma is the microwave-induced plasma (MIP). The MIP usually utilises helium and is therefore very highly ionising. It suffers far fewer interference problems than argon-based plasmas, although traditionally it has had the reputation of not being a very robust plasma, i.e. it is easily extinguished by the 

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In PECVD, the plasma generation region may be in the deposition chamber or precede the deposition chamber in the gas flow system. The latter configuration is called remote plasma-enhanced CVD (RPECVD). In either case, the purpose of the plasma is to give activation and partial reaction/reduction of the chemical precursor vapors so that the substrate temperature can be lowered and still obtain deposit of the same quaUty. 

At 70—140°C, peroxide is vaporised. Peroxide vapor has been reported to rapidly inactivate pathogenic bacteria, yeast, and bacterial spores in very low concentrations (133). Experiments using peroxide vapor for space decontamination of rooms and biologic safety cabinets hold promise (134). The use of peroxide vapor and a plasma generated by radio frequency energy releasing free radicals, ions, excited atoms, and excited molecules in a sterilising chamber has been patented (135). 

Operation of the installation is as follows. The power supply (1) is connected to the plasma generator (4.5 kW) (2), which initiates a plasma jet by delivering plasma-forming gas (air, oxygen, nitrogen etc.). The solution is loaded onto the plasma by means of pneumatic nozzles (3) and dispersed using the same type of gas. 

Fig. 139. Plasma chemical installation. 1 - Plasma generator 2 — plasma torch 3 - pneumatic nozzles 4 — reactor 5 - solid parts collector 6 — fine filter 7 - heat exchanger 8 - condensate collector.

II. Plasma-Generated Trifluoromethyl Radicals as a Synthetic Reagent.. . 181... 

For completeness, it should be mentioned that the reaction of trifluoromethyl radicals to replace halogens is extremely general, and not confined solely to metal species. Plasma-generated trifluoromethyl radicals will react with halocarbons according to the reaction 21)... 

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. 

Corona discharge is the simplest type of plasma generator. A feature of the corona discharge, which differentiates it from the other discharges, is that no dielectric is involved. Instead, an electron avalanche is initiated from a sharp metallic surface where the radius of curvature is small. The electric field has to be pulsed in order to prevent the plasma from going into the thermal mode and forming an arc. The electric field in corona reactors is about 50 kV/cm. 

Khacef, A., Cormier, J.M. and Pouvesle, J.M. (2002) NOx remediation in oxygen-rich exhaust gas using atmospheric pressure non-thermal plasma generated by a pulsed nanosecond dielectric barrier discharge, J. Phys. D Appl. Phys. 35, 1491-8. 

FIGURE 5.5 Standard curve of compound A in rat plasma generated by MRM. 

Figure 3.1. Multichamber deposition system for organic light emitting diodes (S sample, RF 02 plasma generator, P vacuum pump, Sh shutter, Q quartz microbalance, C crucibles, M mask for electrode patterning, T tungsten wires for metal deposition).

Turner IL, Montaser (1998) Plasma generation in ICPMS. In Inductively Coupled Plasma Mass Spectrometry. Montaser A (ed),. Wiley-VCH, New York, p 265-334... 

Polypropylene (PP) is a hydrophobic and chemically inert polymer which needs to be activated in order to be functional as a support for NA immobilization. Typically, PP membranes are aminated by exposure to an ammonia plasma generated by radiofrequency plasma discharge. Once aminated, the PP membranes can be reacted with derivatized ONDs using common coupling methods [56-58]. 

C—C and C—F bond strengths, 23 181-182 and plasma generation of trifluoro-methyl radicals, 23 180-192 Hexafluorogermanate ion charge distribution, 22 73 enthalpy, 22 73 halide ion affinity, 22 74 lattice energy, 22 73 radius, 22 73, 74 structure, 22 73... 

The liquid corona technology can treat hazardous or toxic organic contaminants in water. When the technology is used to treat water, the plasma generates very reactive species that react with the contaminants in the water. The technology developer claims that the technology is very effective on materials that are recalcitrant to other methods of destruction. 

Researchers claim that generating a plasma using a high-frequency power source generally leads to a plasma that is easier to handle, more efficient, and less expensive than plasmas generated by direct current (DC) power sources. 

R. Friedman, Raketnaya Tekhnika No 1, p 122(1961) (Solid Powders as Sources of Cesium Plasma) 17) R.C. Good Jr, AIAA-Jour, Vol 1, No 6, 1397-1402 (June 1963) ( Destructive Effects of Plasmas Generated by Exploding Wires ) 18) W.G. Chace H.K. Moore, Eds, Exploding Wires ,... 

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