Scott chamber design

An aerosol generated by nebulization is directed through a spray chamber (nebulizer chamber). This is usually made of glass, quartz, or inert polymers (Ryton or several fluorine-based polymers), which prevents large aerosol droplets from reaching the plasma. The classical Scott chamber design has been superseded by the cyclonic chamber, which has a 50% better sensitivity. 

Three different spray chamber designs (Fig. 3.6) are most often used for ICP-MS the Scott [15] (double-barrel) chamber, a conical chamber with an impact bead, and a cyclonic chamber [14,16,17]. The cyclonic spray chamber typically provides a slightly (up to about a factor of 2 or 3) higher analyte transport efficiency as well as somewhat shorter washout times. In some cases the spray chamber is cooled (such as on the HP 4500 ICP-MS double-pass spray chamber, which is cooled to 4°C) to reduce the amount of water vapor that enters the ICP further so that signals from polyatomic ions containing oxygen are reduced. The cooled spray chamber also helps maintain a stable spray chamber temperature. 

Figure 6 Spray chambers (a) Scott, double-pass design, (b) Conical chamber with impact bead, (c) Cyclone spray chamber (top view), (d) Cyclone spray chamber (side view).

In the cyclonic spray chamber droplets are discriminated according to their size by means of a vortex produced by the tangential flow of the nebulizer. Smaller droplets are transferred with the sample aerosol into the ICP-MS, while the larger droplets collide with the walls and exit by gravity via a drain tube. If compared to the Scott design, the cyclonic spray chamber typically shows higher sensitivity. 

A second popular type of spray chamber utilizes a cyclonic design. A diagram of this spray chamber is shown in Figure 5.10. Instead of using two compartments as with the Scott-type spray chambers, this device uses a... 

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