Aerosol generation and sampling

TABLE XIX. Comparison of the precision of the aerosol generation and sampling system with the analytical precision obtained by using the ruggedized method. 

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. 

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-... 

Fundamental Processes That Control Aerosol Generation and Transport. The size of the aerosol drops in the initial (primary) aerosol depends on the design of the nebulizer, the nebulizer gas flow rate, and, to a lesser extent, the sample... 

Raabe OG. In Liu BYH, ed. Fine Particles Aerosol Generation, Measurements, Sampling and Analysis. New York Academic Press, 1976 57-110. 

A sampler is able to produce a sample no more accurate than the sample presented to it. The main consideration in the location of the sample probe is whether it sees the center one-third of the pipeline and whether it is in an area where there is good velocity with minimum turbulence. Turbulence is an aerosol generator and therefore, liquids put into flight by the turbulence may affect the sample s result. This turbulence makes the... 

A pulsed sample introduction (PSI) interface and laser-induced multiphoton ionization have been also used to couple LC with TOF instruments [56]. The interface consists of a heated capillary for aerosol generation and a high-temperature pulsed nozzle for sample vaporization. The LC effluent enters the heated capillary at a flow rate between 0.5 and 1.6 mLmin A solenoid allows the sample vapor to enter the mass spectrometer in a pulse form. 

For non-volatile sample molecules, other ionisation methods must be used, namely desorption/ionisation (DI) and nebulisation ionisation methods. In DI, the unifying aspect is the rapid addition of energy into a condensed-phase sample, with subsequent generation and release of ions into the mass analyser. In El and Cl, the processes of volatilisation and ionisation are distinct and separable in DI, they are intimately associated. In nebulisation ionisation, such as ESP or TSP, an aerosol spray is used at some stage to separate sample molecules and/or ions from the solvent liquid that carries them into the source of the mass spectrometer. Less volatile but thermally stable compounds can be thermally vaporised in the direct inlet probe (DIP) situated close to the ionising molecular beam. This DIP is standard equipment on most instruments an El spectrum results. Techniques that extend the utility of mass spectrometry to the least volatile and more labile organic molecules include FD, EHD, surface ionisation (SIMS, FAB) and matrix-assisted laser desorption (MALD) as the last... 

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