Spray chambers impact bead

In the premix burner, the sample, in solution form, is first aspirated into a nebulizer where it forms an aerosol or spray. An impact bead or flow spoiler is used to break the droplets from the nebulizer into even smaller droplets. Larger droplets coalesce on the sides of the spray chamber and drain away. Smaller droplets and vapor are swept into the base of the flame in the form of a cloud. An important feature of this burner is that only a small portion (about 5%) of the aspirated sample reaches the flame. The droplets that reach the flame are, however, very small and easily decomposed. This results in an efficient atomization of the sample in the flame. The high atomization efficiency leads... 

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).

A negative effect found when working at low hquid flow rates is an increase in wash-out times, leading to a subsequent drop in sample throughput In order to mitigate this problem, new low inner volume spray chambers have been developed and their performance has been tested in ICP-MS. For a mini cyclonic spray chamber, called the Cinnabar, wash-out times were found to be significantly shortened with respect to a double pass spray chamber for the analysis of iodine species. Due to its simplicity and the small dispersion provided by this spray chamber, it has also been successfully applied as part of a CE-ICP-MS interface. Low inner volume single pass spray chambers have also been used in various ways as aerosol transport devices for ICP-MS, namely with the nebuliser directly connected to them, with an impact surface (i.e. bead) inside them and as part of a CE-ICP-MS interface. ... 

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