Nebulization chamber

Weber, R.E., Wang, L.K., and Pavlovich, J., Separation of Liquids with Different Boiling Points with Nebulizing Chamber, U.S. Patent 5,156,747, 1992. 

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 The classical Scott chamber design has been superseded by the cyclonic chamber, which has a 50% better sensitivity. 

Gas chromatography-atomic absorption (AA) has gained popularity because the interfacing is quite simple. In its crudest form, the effluent from the GC column is directly connected to the nebulization chamber of the AA. Here, the effluent is allowed to be swept into the flame by the oxidant and flame gases. There have been several recent reviews of the technique [127,128]. 

The key to a successful HPLC-ICP-MS coupling is the interface. In the simplest case the outlet of an HPLC column (4.6 D10 mm) is connected to a conventional pneumatic or crossBow nebulizer. The use of capillary or megabore (0.32D1.0mm) HPLC systems that are becoming popular, especially for RPC, requires the use of micronebulizers, either direct injection nebulizers (DIN) or micronebulizers (e.g., Micromist, DS-5) bttcd with a small-volume nebulization chamber. 

In ultrasonic nebulizers, ultrasound waves (Fig. 2) are formed in an ultrasonic nebulizer chamber by a ceramic piezoelectric crystal that vibrates when electrically excited. These set up high-energy waves in the solution, within... 

Direct injection nebulizers, as they were first described by Kimberley et al. [121], are used without a nebulization chamber. In this way sample losses are low as... 

Fig. 48. ICP-MS coupled on-line to liquid HHPN nebulization chamber, (5) desolvation...

Fig. 98. ICP-optical emission spectrometer, (a) gas supply, (b) sampler, (c) peristallic pump, (d) nebulizer, (e) nebulization chamber, (f) hf generator, (g) ICP torch, (h) spectral apparatus, data acquisition, data processing.

Maximum dissolved solids nebulizers [111] are usually cross-flow nebulizers operated at a high pressure. They are often made from PTFE, including the capillaries, and thus can be used for work with HF containing solutions. In this case a nebulization chamber made of PTFE and an ICP torch with an internal tube made of AI2O3 ceramics or BN should be used. 

The two main causes are the evaporator tube heating coil and/or the nebulizing chamber. The chamber can usually be cleaned with a bottle brush. The tube can be heated to 100 °C and with some luck the contamination disappears within a few minutes. After cooling the tube must be rinsed thoroughly with a suitable mobile phase. 

For inhalation treatment of respiratory diseases, a pharmaceutical DNase I aerosol is on the market. Pulmozyme is a sterile solution for respiratory use at a concentration of 1000 Genentech Units/mL [22]. It contains 1 mg/mL rhDNase, sodium chloride as a tonicity modifier, calcium chloride as a stabilizer, and water for injection. Since deamidation is rapid at high pH and aggregation occurs at low pH, a nearly neutral solution (pH 6.3) is required. It is administered by means of a compressed air-driven nebulizer. Each 2.5-mL single-unit ampule will deliver 2.5 mg of rhDNase to the nebulizer chamber. The efficacy of DNase inhalation therapy largely depends on the aerosol quality and characteristics, which determine the respirable fraction. Significant differences were found between the different aerosol drug-delivery systems [68,81]. 

The interference by copper on the determination of iodide is explained by the following reaction taking place in the nebulization chamber ... 

Other burners separate the nebulization process and the flame by producing small liquid droplets in a nebulizing chamber before the sample enters the flame. Figure 10-12 shows this process in the Perkin-Elmer unit. 

FIGURE 10-12. Perkin-Elmer atomic absorption sample cell showing nebulizing chamber and burner. [Courtesy the Perkin-Elmer Corp.]... 

HHPN nebulization chamber, (5) desolvation system with heating and two-stage cooling, (6) ICP torch, (7) drain. (Reprinted with permission from Ref. [131].)... 

Aerosol droplet size di.stributions can be determined by stray-light measurements [87], [88]. Data obtained from sampling with cascade impac-tors may suffer from evaporation of the droplets on their way through the device, especially as sampling may require the application of underpressure [89]. Data for different nebulizers are available [90]. Particle size distributions depend on the nebulizer and its working conditions, on the liquid nebulized, and on the nebulization chamber. These relations have been studied in depth for organic solutions [91], [92], for which, at low gas flow, pneumatic nebulizers often... 

The sample droplets collect at the bottom of the nebulization chamber and the deaerated solution is transferred to the cell (sensing electrodes in the cell ensure that an appropriate volume is transferred). 

In the spectral analysis of solutions, the nebulizer is generally placed in a nebulization chamber with a drain to compensate for fluctuations in nebulizer operation as well as for separating off the large droplets so as to remove inappropriate liquid deposits in the sample uptake system. The nebulization chamber together with the torch and the nebulizer form a unit, and the dimensions and form of each component have to be considered in optimization work. Nebulization systems have frequently been compared throughout the whole development of solution... 

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