Nebulization principle

Hess, D.R. 2000. Nebulizers principles and performance. Respir. Care 45 609-622. 

Droplet Formation. A general theory for the formation of droplets by nebulization has not been fully developed, although the understanding of the nebulization principle has been improved with mathematical... 

HaloLite, shown in Fig. 11, is a hand-held drug delivery system developed by Medic-Aid (Bognor Regis, United Kingdom). The device, which uses compressed air, consists of a medication chamber, a control unit, and an aerosol generation assembly that is operated by a portable, dedicated compressor. The aerosol is generated based upon conventional nebulization principles. The control unit allows the patient to select a... 

A completely new nebulizer principle was introduced in the late 1990s [151]. A vibrating multicrifice plate system was employed. This electronic system does not require the cumbersome air pump of the jet nebulizers and employs a principle that can be scaled up to handheld systems [152]. 

Berndt H. and Yanez J. (1996) High-temperature hydraulic high-pressure nebulization a recent nebulization principle for sample introduction, J Anal At Spectrom 11 703-712. 

Nebulizers can be divided into several main types. The pneumatic forms work on the principle of breaking up a stream of liquid into droplets by mechanical means the liquid stream is forced through a fine nozzle and breaks up into droplets. There may be a concentric stream of gas to aid the formation of small droplets. The liquid stream can be directed from a fine nozzle at a solid target so that, on impact, the narrow diameter stream of liquid is broken into many tiny droplets. There are variants on this approach, described in the chapter devoted to nebulizers (Chapter 19). 

Nebulizers are used to introduce analyte solutions as an aerosol spray into a mass spectrometer. For use with plasma torches, it is necessary to produce a fine spray and to remove as much solvent as possible before the aerosol reaches the flame of the torch. Various designs of nebulizer are available, but most work on the principle of interacting gas and liquid streams or the use of ultrasonic devices to cause droplet formation. For nebulization applications in thermospray, APCI, and electrospray, see Chapters 8 and 11. 

The basic principle of APCI consists in nebulizing the effluent that is transferred through a heated vaporizer allowing complete evaporation of the solvent. A corona discharge electrode is placed in the source next to the vaporizer and produces electrons initiating the... 

A promising detection principle utilizes similar nebulization procedure as applied in ELS, namely the corona-charged aerosol detectors, CAD. In CAD, the aerosol particles interact with an ionized gas (usually nitrogen). The particles become charged and electrically detected [294]. It has been shown that the response of CAD does not depend on the nature of analyte. On the other hand, the size of the aerosol depends on the mobile phase composition and it has to be calibrated. 

On which principle is the operation of a pneumatic nebulizer based—explain how this works ... 

The reaction of aerosol droplets with gases can also be used to prepare particles of internally mixed composition, such as consisting of different metal oxides. In principle, these powders can be obtained by first cocondensing vapor of the two or more volatile metal compounds (preferably alkoxides), or by nebulizing liquids of mixed composition. In both cases the droplets are then reacted with vapors. 

The basic set-up and compounds of an ICP-AES and ICP-MS are shown in Fig. 2. The ICP part is almost identical for AES and MS as detection principle. The ICP torch consists of three concentric quartz tubes, from which the outer channel is flushed with the plasma argon at a typical flow rate of 14 1 min-1. This gas flow is both the plasma and the cool gas. The middle channel transports the auxiliary argon gas flow, which is used for the shape and the axial position of the plasma. The inner channel encloses the nebulizer gas stream coming form the nebulizer / spray chamber combination. This gas stream transports the analytes into the plasma. Both the auxiliary and the nebulizer gas flow are typically around 1 1 min-1. The plasma energy is coupled inductively into the argon gas flow via two or three loops of a water-cooled copper coil. A radio frequency of 27.12 or 40.68 MHz at 1-1.5 kW is used as power source. The plasma is... 

Large droplets for recirculation Figure 10.6 Principles of operation of an airjet nebulizer... 

The APPI source is one of the last arrivals of atmospheric pressure sources [80,81]. The principle is to use photons to ionize gas-phase molecules. The scheme of an APPI source is shown in Figure 1.34. The sample in solution is vaporized by a heated nebulizer similar to the one used in APCI. After vaporization, the analyte interacts with photons emitted by a discharge lamp. These photons induce a series of gas-phase reactions that lead to the ionization of the sample molecules. The APPI source is thus a modified APCI source. The main difference is the use of a discharge lamp emitting photons rather than the corona discharge needle emitting electrons. Several APPI sources have been developed since 2005 and are commercially available. The interest in the photoionization is that it has the potential to ionize compounds that are not ionizable by APCI and ESI, and in particular, compounds that are non-polar. 

Rau, J. L. (2002), Design principles of liquid nebulization devices currently in use, Respir. Care, Al, 1257-1275 discussion 1275-1278. 

The vibrating membrane nebulizer is currently under development by Pari GmbH, (Germany), which is based upon the TouchSpray technology developed by The Technology Partnership pic (United Kingdom). The main aerosol generation principle is similar to that... 

The important features of the sample preparation procedure were as follows. First, the samples were acidified to dissolve normal urine precipitates and to prevent analyte loss by adsorption on the walls of the sample containers (13). Second, the procedure was kept as simple as possible so that the risk of contamination and/or loss was minimized. Third, dilute, normal, and concentrated series of solutions were used to simulate actual urine samples with a wide range of total dissolved solids. Fourth, because the rate of sample nebulization and the corresponding rate of sample introduction into the plasma can be aflFected by changes in the amount of total dissolved solids, internal reference elements were included in each sample and reference solution. The use of analyte/internal reference element net intensity ratios provided a means of correcting for possible diflFerences in sample introduction rate according to the internal reference principle (14,15). Finally, because all of the sample solutions introduced into the plasma were derived from one composite, the different series were known to have trace element concentrations which were related to each other by known dilution factors (see Table IV). 

Over 30 years of liquid chromatography-mass spectrometry (LC-MS) research has resulted in a considerable number of different interfaces (Ch. 3.2). A variety of LC-MS interfaces have been proposed and built in the various research laboratories, and some of them have been adapted by instmment manufacturers and became commercially available. With the advent in the early 1990 s of interfaces based on atmospheric-pressure ionization (API), most of these interfaces have become obsolete. However, in order to appreciate LC-MS, one carmot simply ignore these earlier developments. This chapter is devoted to the older LC-MS interfaces, which is certainly important in understanding the histoiy and development of LC-MS. Attention is paid to principles, instrumentation, and application of the capillary inlet, pneumatic vacuum nebulizers, the moving-belt interface, direct liquid introduction, continuous-flow fast-atom bombardment interfaces, thermospray, and the particle-beam interface. More elaborate discussions on these interfaces can be found in previous editions of this book. 

The unique detection principle of evaporative lightscattering detectors involves nebulization of the column effluent to form an aerosol, followed by solvent vaporization in the drift tube to produce a cloud of solute droplets (or particles), and then detection of the solute droplets (or particles) in the light-scattering cell. 

Nebulizers can be divided into several main types. The pneumatic forms work on the principle of breaking up a stream of liquid into droplets by mechanical means the liquid stream is forced through a fine nozzle and breaks up into droplets. There may be a concentric stream of gas to aid... 

---