A porous carbon film for the collection of atmospheric aerosol for transmission electron microscopy

This paper describes a method of direct sampling of fine urban aerosol using porous carbon films, to increase collection efficiency and retain the structural integrity of the aerosol. A nuclepore membrane filter was coated with carbon and washed with chloroform to leave a clean porous carbon film on a 200-mesh transmission electron microscope copper grid. The grid was attached to a clean nuclepore filter using carbon cement. Sampling was conducted for 1 h at 1.9 L min⁻¹ flow rate. The porous carbon grid with sample was then assayed using transmission electron microscopy, and negatives were suitable for image analysis. The collection of fine airborne particles using this method is appropriate for electron microscopy, with a minimum of interference to the structure of collected particles.