Nebulization system

Walder AJ, Roller D, Reed NM, Hutton RC, Freedman PA (1993) Isotope ratio measurement by inductively coupled plasma multiple collector mass spectrometry incorporating a high efficiency nebulization system. J Anal At Spectrom 8 1037-1041... 

Greenfield ef. ai.l l) observed a reduction of signal intensity that correlates with sample intake effects from the modified solution viscosity and/or surface tension of mineral acids. This, coupled with peristaltic pumping of solutions into the nebulizer, considerably reduces physical interferences. Increased salt concentration also has an effect on solution physical properties. In the experience of these authors, the high levels of salt in the matrix also increases the noise from the nebulizer system. This degradation of nebulizer performance, which is not necessarily accompanied by a proportional reduction in sensitivity, is the cause of the observed deterioration of detection limits in real samples as opposed to ideal solutions. 

Care must be taken to ensure complete removal of HF (or effective removal by H3BO3 complexation), as any free acid degrades the glassware of the nebulizer system. LiB02 is a flux that decomposes most silicates, keeping Si02 in solution for analysis. 

Do not exceed the maximum daily dose of 8 mg with an intermittent flow nebulization system or 14 mg with a continuous flow nebulization system. 

Figure 2.7 shows a typical pneumatic nebulization system for a premixed flame. The sample is sucked up a plastic capillary tube. In the type of concentric nebulizer illustrated here, the sample liquid is surrounded by the oxidant gas as it emerges from the capillary. The high velocity of this gas, as it issues from the tiny annular orifice, creates a pressure drop which sucks up, draws out and shatters the liquid into very tiny droplets. This phenomenon is known as the venturi effect and is illustrated in Fig. 2.8. 

Schematic diagram of a concentric nebulizer system for a premixed burner.

Route of administration Pulmozyme is administered by inhalation of an aerosol mist produced by a compressed-air-driven nebulizer system. 

Nebulizer systems are universally aqueous in nature and can be either solution or suspension based. Excipients that have been used in nebulizer formulations relate to typical aqueous formulations and the formulation issues common to this type of preparation (i.e., stability and sterility issues). Table 3 provides several examples of nebulizer formulations that are commonly marketed along with the excipients... 

The analytical performance of atomic detectors in terms of sensitivity, selectivity and resolution has been markedly improved by the use of USNs. However, the utility of these nebulization systems is not exclusive of atomic detectors as, in fact, USNs have been successfully implemented in electrospray formation devices, which are employed as inter-faoes between separation techniques such as CE or HPLC and mass detection [8]. 

Potential solutions to these challenges to ensure effective inhalation drug treatment include active dry powder delivery systems, active liquid blister technology, and hydrofiuorocarbon (HFC) propellant nebulization systems. 

Nebulizers have a long history in pulmonary delivery. Although generally effective, traditional nebulizer systems require lengthy (10-20 min) administration periods during which drug solution is delivered with relative inefficiency using an external power source. 

Pillai, R.S. Hughes, B.L. Wolff, R.K. Heisserman, J.A. Dorato, M.A. The effect of pulmonary-delivered insulin on blood glucose levels using two nebulizer systems. J. Aerosol Med. 1996, 9, 227-240. 

The specific design of the various sample introduction devices or spray probes depends to a large extent on the technique applied, i.e., ESI, APCI, or other. With respect to ESI, systems have been described for conventional pure ESI, pneumatically-assisted ESI or ionspray, ultrasonically-assisted ESI, thermally-assisted ESI, and micro- and nano-ESI (Ch. 5.5). The heated-nebulizer system (Ch. 5.6.2) is used in APCI and atmospheric-pressure photoionization (APPI). 

Nebulizers are widely used today for drug delivery to the respiratory tract and are particularly useful for the treatment of hospitalized or nonambulatory patients. Fundamentally, there are two general types of nebulizer systems, the ultrasonic and the air jet. 

Eisenberg J, Pepe M, Williams-Warren J, Vasiliev M, Montgomery AB, Smith AL, Ramsey RW. A comparison of peak sputum tobramycin concentration in patients with cystic fibrosis using jet and ultrasonic nebulizer systems. Chest 111 955-962, 1997. 

Newman SP, Woodman G, Clarke SW. Deposition of carbenicillin aerosol in cystic fibrosis effects of nebulizer system and breathing pattern. Thorax 1988, 43, 318-322. 

Apart from continuous sample aspiration also flow injection and discrete sampling can be applied (see Section 3.1), both of which deliver transient signals. In the latter case 10-50 pi aliquots can be injected manually or with a sample dispenser into the nebulization system, as was first proposed by Ohls et al. [125] and described by Bemdt et al. (see Ref. [126]). The approach is especially useful for preventing clogging in the case of sample solutions with high salt contents, for the analysis of microsamples as required in semm analysis or when aiming at the... 

Posta J. and Berndt H. (1992) A high-performance flow/hydraulic high pressure nebulization system (HPF/ HHPN) in flame AAS for improved elemental trace determinations in highly concentrated salt solutions, Spectrochim Acta, Part B 47 993-999. 

A Jarrell-Ash Model 82-532 MV spectrophotometer equipped with a Perkin Elmer nebulization system and a Leeds-Northrup Type W calibrated AZAR Recorder was used for the molybdenum analysis. The 3133 primary molybdenum absorption wavelength coupled with an acetylene-nitrous oxide flame were the basic parameters of the instrument. The recorder was set for a 5-fold signal expansion along with the amplifier at 3/4 damped position. 

The amount of liquid and the droplet size created by the nebulizer system are the most important factors influencing the sensitivity. The droplet size itself is also dependent on density, viscosity and surface tension of the solution. An empirically derived formula was given by Nukiyama and Tanasawa (1938-1940). 

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