Abstract: A device having an air sampler, an electrospray apparatus, and a fluorescence excitation and detection system. The air sampler is capable of moving air suspected of containing a biological or chemical aerosol particle into a chamber. The electrospray apparatus is capable of spraying a charged solution into the chamber to coat the aerosol particles with a coating. The solution has a fluorescent-labeled biological or chemical marker capable of specific binding to the aerosol particle. The fluorescence system is capable of detecting fluorescence of the fluorescent label in the coating. A method of detecting the aerosol particle by: moving air suspected of containing the aerosol particle into a chamber; spraying the charged solution into the chamber with an electrospray apparatus, such that a coating of the solution is formed around the particle; exciting the fluorescent label; and detecting fluorescence of the fluorescent label.

Abstract: A displacement-type flow immunoassay is performed using a microcapillary passage. The inner wall of the microcapillary passage has immobilized thereon antibodies to the antigen of interest. Labeled antigen is immunologically bound to the immobilized antibodies. Sample antigen passing through the column displaces the labeled antigen. Downstream, the displaced labeled antigen is detected. The microcapillary format of the present invention enhances the sensitivity of the immunoassay over the sensitivity of displacement-type flow immunoassays performed in a column at similar flow rates.