TEM used to detect copper in e-cigarette vapor
E-cigarettes have become quite popular recently and have a reputation of being less harmful than regular cigarettes. However, few analyses have been done on the smoke or vapors emitted from these devices. There is some evidence that the emitted vapor contains metallic nanoparticles but it has been difficult to characterize these particles.
A procedure to examine particles collected on aluminum impact filters has been developed at CEMAS to allow Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), and Energy-dispersive X-ray spectroscopy (EDX) examination of these nanoparticles. After heating to remove most of the organic material from the vapors, two stage carbon replicas were prepared from the aluminum filter disks. These were then further cleaned using a low power Ultraviolet treatment to minimize organic buildup under the electron beam.
High angle annular dark field (HAADF) STEM images from the CEMAS Tecnai F20 TEM clearly show the presence of particles less than 20nm in size. EDX mapping of the sample indicates that the nanoparticles are copper.
Hendrik O. Colijn1, Vladimir Mikheev2, David W. McComb1
1 Center for Microscopy and Analysis, The Ohio State University, Columbus, OH, USA.
2. Battelle Memorial Institute, Columbus, OH