Alternate Potential Mass Spectrometric Methods for Sizing and Chemical Composition

FIGURE 11.73 Schematic diagram of aerosol mass spectrometer for volatile and semivolatile particle sizing and composition measurement (graciously provided by J. Jayne, D. Worsnop, and C. Kolb, 1999). 

FIGURE 11.74 Schematic diagram of aerosol particle mass spectrometer for measurement of composition of continuous beams of volatile and semivolatile particles (graciously provided by P. Zie-mann, 1998). 

Both of these approaches are hence useful for a continuous stream of particles of similar composition where the mass spectrum can be continuously scanned, for example in laboratory environmental chamber studies. 

In summary, the use of mass spectrometric methods, combined with various approaches to vaporizing and ionizing the particles, is gaining increasing popularity and interest for the analysis of continuous sources of particles or single particles. The problem of quantification of the components seen by single-particle laser ionization techniques remains to be solved. On the other hand, the vaporization approaches can provide quantitative data on some volatile and semivolatile components but cannot measure the nonvolatile species and, at present, do not provide a full mass spectrum for a single particle. 

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