Aerosol-Based Detection Methods

In the past, aerosol-based detection methods such as evaporative light scattering detection (ELSD), condensation nucleation light scattering detection 

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In the last few years, new procedures were developed for PAH analysis using MS-based detection methods. GC-IT-MS and a laser desorption-IT-MS screening method were applied to the analysis of airborne particulate-associated PAHs. Direct screening of aerosol filter samples were carried out using laser desorption TOF-MS. Isotope dilution techniques using GC-MS were also developed for some PAHs, such as benzo[a]pyrene. 

Dixon RW, Development and testing of a detection method for liquid chromatography based on aerosol charging , Analytical Chemistry 2002 74 2930-2937. 

Ricin can be detected in the blood or other bodly fluids of exposed animals using competitive radioimmunoassays or enzyme-linked immunosorbent assays (ELISA). These methods generally do not distinguish between active ricin molecules versus partially degraded or otherwise inactivated toxin. The postexposure time limit for accurate antibody-based detection of ricin in biological samples varies and depends on the route of exposure and the absorbed dose. In the laboratory, ELISA detects ricin in oro-nasal swabs of NHP exposed to ricin aerosol up to 24 h after exposure (Franz and Jaax, 1997). Likewise, ELISA detects ricin in selected tissues of laboratory rats up to 48 h after an i.m. challenge (Leith et al., 1988). 

Continuous Sampling and Determination. There are no truly continuous techniques for the direct determination of sulfuric acid or other strong acid species in atmospheric aerosols. The closest candidate method is a further modification of the sensitivity-enhanced, flame photometric detector, in which two detectors are used, one with a room-temperature de-nuder and one with a denuder tube heated to about 120 °C. Sulfuric acid is potentially determined as the difference between the two channels. In fact, a device based on this approach did not perform well in ambient air sampling (Tanner and Springston, unpublished data, 1990). Even with the SF6-doped H.2 fuel gas for enhanced sensitivity, the limit of detection is unsuitably high (5 xg/m3 or greater) because of the difficulty in calibrating the two separate FPD channels with aerosol sulfates. 

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