Generation, aerosol

The traditional way of introducing a liquid sample into an analytical plasma can be considered as two separate events aerosol generation using a nebulizer and droplet selection using a spray chamber.  

As mentioned previously, the main function of the sample introduction system is to generate a fine aerosol of the sample. It achieves this with a nebulizer and a spray chamber. The sample is normally pumped at about 1 mL/min via a peristaltic pump into the nebulizer. A peristaltic pump is a small pump with lots of minirollers that all rotate at the same speed. The constant motion and pressure of the rollers on the pump tubing feeds the sample through to the nebulizer. The benefit of a peristaltic pump 

Practical Guide to ICP-MS A Tutorial for Beginners, Second Edition 

FIGURE 3.2 More detailed view of the ICP-MS sample introduction area. 

FIGURE 3.3 Conceptual representation of aerosol generation using a cross-flow nebulizer. 

Once the sample enters the nebulizer, the liquid is then br( en up into a fine aerosol by the pneumalic action of a flow of gas (-1 L/min) smashing the liquid into tiny droplets, very similar to the spray mechanism in a can of deodorant. It should be noted that although pumping the sample is the most common approach to introducing the sample. 

FIGURE 3.3 The stability of a continuous ICP-MS signal with a syringe pump compared 

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B. W. Loo, J. M. JaMevic, and F. S. Goulding, "Dichotomous Virtual Impactors for Large Scale Monitoring of Airborne Particulate Matter," in B. Y. H. Liu, ed., Eine Particles, Aerosol Generation, Measurement, Sampling and Analysis, Academic Press, Inc., New York, 1976, pp. 311—350. 

B. Y. H. Liu, ed.. Tine Particles—-Aerosol Generation, Measurement, Sampling and Analysis, Academic Press, Inc., New York, 1976. 

A water-soluble white crystalline sofld, CS is disseminated as a spray, as a cloud of dust or powder, or as an aerosol generated thermally from pyrotechnic compositions. The formulation designated CSl is CS mixed with an anti-agglomerant when dusted on the ground, it may remain active for as long as five days. CS2 formulated from CSl and a siUcone water repellent, may persist for as long as 45 days (6). 

For determination of the aerodynamic diameters of particles, the most commonly apphcable methods for particle-size analysis are those based on inertia aerosol centrifuges, cyclones, and inertial impactors (Lundgren et al.. Aerosol Measurement, University of Florida, Gainesville, 1979 and Liu, Fine Paiiicles—Aerosol Generation, Measurement, Sampling, and Analysis, Academic, New York, 1976). Impactors are the most commonly used. Nevertheless, impactor measurements are subject to numerous errors [Rao and Whitby, Am. Ind. Hyg. A.s.soc.]., 38, 174 (1977) Marple and WiUeke, "Inertial Impactors, in Lundgren et al.. Aerosol Measurement and Fuchs, "Aerosol Impactors, in Shaw, Fundamentals of Aerosol Sci-... 

V) SiiUcr el al., Aerosols Generated by Free Fall Spills of Powders and Solutions in Sialie Air, 1981... 

Ballinger and Hodgson, Aerosols Generated by Spills of Viscous Solutions and Slurries, 1986. 

Powers, D. A, et al., I985, VANESA, A Mechanistic Model of Radionuclide Release and Aerosol Generation during Core Debris Interaction with Concrete, NUREG/CR-4308. 

Other Applications Very small, very low-flow, and relatively high-velocity exhaust inlets, similar to LVHV nozzles, have been used successfully to control fumes from electric soldering irons." " Some investigations have been made into small, point-control exhaust ventilation for aerosols generated by high-speed dental tools. However, such low-volume point-control ventilation systems have not seen widespread use. 

In addition, even where foaming is not a specific problem in a boiler, carryover may occur, especially in lower pressure boilers with very high TDS (i.e., over 10,000 to 15,000 ppm TDS) because of the collapse of surface bubbles. This leads to BW aerosol generation and entrainment of the spray in steam. Under these circumstances, antifoam agents such as polyamides are useful in preventing these entrainment problems. Furthermore, the antifoaming action of polyamides is often enhanced by protective colloid materials such as tannins, and consequently, formulations containing polyamide emulsions in an alkaline tannin base are available. 

Ribavirin The patient is told that this drug is given with a small-particle aerosol generator. Any worsening of respiratory function, dizziness, confusion, or... 

MAGIC (Monodisperse Aerosol Generating Interface for Chromatography), Thermabeam and Universal interfaces. 

SRM 1876b is intended for use in evaluating transmission electron microscopy (TEM) techniques used to identify and count chrysotile fibers. This SRM consists of sections of mixed-cellulose-ester filters containing chrysotile fibers deposited by an aerosol generator. 

Figure 9.5 Scheaatic diagraa of the aonodlsperse aerosol generation Interface (MAGIC) for LC/MS with Insert providing a nore detailed view of the eluent nebuliser and particle beae oaentun separator.

The droplet size delivered from a vibrating orifice monodisperse aerosol generator can be derived from the following expressions ... 

AJ Hickey, RM Evans. Aerosol generation from propellent-driven metered dose inhalers. In AJ Hickey, ed. Inhalation Aerosols. New York Marcel Dekker, Inc., 1996, pp. 417-439. 

Aerosols generated by electrical heating of a coil of nichrome wire Aerosol Size Range 0.01 - 0.08 urn (radius)... 

J.D. Jordan, R.A. Dunbar, and F.V. Bright, Aerosol-generated sol-gel-derived thin films as biosensing platforms. Anal. Chim. Acta 332, 83-91 (1996). 

Figure 5.21. Torch and sample aerosol generation system (QVAC 127 system). Source [510]...

If an aerosol generating device is employed (e.g., sprayer), or the dissemination method is unknown and the release is ongoing, then responders should wear a Level A protective ensemble. Once the device has stopped generating the aerosol or has been rendered inoperable, and the aerosol has settled, then responders can downgrade to Level B. 

A number of conditions must be considered when selecting protective equipment for individuals at the scene of a release. For instances such as "anthrax" letters when the mechanism of release is known and it does not involve an aerosol generating device, then responders can use Level C with high-efficiency particulate air (HEPA) filters. 

Ribavirin may be considered for bronchiolitis caused by respiratory syncytial virus in a subset of patients (those with underlying pulmonary or cardiac disease or with severe acute infection). Use of the drug requires special equipment (small-particle aerosol generator) and specifically trained personnel for administration via oxygen hood or mist tent. 

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