Argon stream

The liquid sample flows into the nozzle and coats the inside walls. The sample stream arrives at the orifice (the nozzle outlet is about 0.01 cm diameter), where it meets the argon stream and is nebulized. 

To assist evaporation of solvent, the argon stream carrying the aerosol can be passed through a heated tube called a desolvation chamber, operated at temperatures up to about 150°C. 

The inductively coupled plasma source (Fig. 20.11) comprises three concentric silica quartz tubes, each of which is open at the top. The argon stream that carries the sample, in the form of an aerosol, passes through the central tube. The excitation is provided by two or three turns of a metal induction tube through which flows a radio-frequency current (frequency 27 MHz). The second gas flow of argon of rate between 10 and 15 L min-1 maintains the plasma. It is this gas stream that is excited by the radio-frequency power. The plasma gas flows in a helical pattern which provides stability and helps to isolate thermally the outside quartz tube. 

For the majority of applications, the sample is taken into solution and introduced into the plasma as an aerosol in the argon stream. The sample solution is pumped by a peristaltic pump at a fixed rate and converted into an aerosol by a nebulizer (see atomic absorption spectrometry). Various designs of nebulizer are in use, each having strengths and weaknesses. The reader is directed to the more specialist texts for a detailed consideration of nebulizers. There is an obvious attraction in being able to handle a solid directly, and sample volatilization methods using electric spark ablation, laser ablation and electrothermal volatilization have also been developed. 

This protocol was described for immediate use. Otherwise, 1 recommend that the N14S slides be dried under an argon stream, sealed and stored at 4°C rmtil needed for printing. Always allow slides to warm to room temperature before opening to avoid moisture condensation that can inactivate the surface chemistry. 

Fullerenes can also be obtained by pyrolysis of hydrocarbons, preferably aromatics. The first example was the pyrolysis of naphthalene at 1000 °C in an argon stream [58, 59], The naphthalene skeleton is a monomer of the Cjq structure. FuUerenes are formed by dehydrogenative coupUng reactions. Primary reaction products are polynaphthyls with up to seven naphthalene moieties joined together. FuU dehydrogenation leads to both Cjq as well as C7Q in yields less than 0.5%. As side products, hydrofuUerenes, for example CjqHjj, have also been observed by mass spectrometry. Next to naphthalene, the bowl-shaped corannulene and benzo[k]fluoranthene were... 

A stream of argon is added after the condenser is in place to drive the cyclopropene into the cold trap. If the argon stream is too strong, cyclopropene will be blown out of the cold trap, thereby affecting the yield. 

Initially the coal-argon stream was fed with the main gas flow supplying the jet. However, the coal particles then had to pass the cathode (whose tip... 

Immerse the clean AuE in a 40 mmol L 1 MPA solution in EtOH/ H202 (75/25, v/v) for at least 15 h to form the MPA-SAM. Rinse the modified electrode with deionized water and dry with an argon stream. 

There are two popular types of plasma sources l) the direct current plasma (DCP), and 2) the inductively coupled plasma (ICP). In the commercial version of the former plasma source (marketed by Spectrometries, Inc.), the sample is aspirated with argon through a small orifice into a chamber where the large droplets settle out and the fine mist is conveyed by the argon stream through a chimney to the vertex of a plasma which is in the form of... 

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