Examining Elemental Surface Enrichment in Ultrafine Aerosol Particles Using Analytical Scanning Transmission Electron Microscopy

Details

• Personal Author:
  Arslan I ; Browning N ; Ito I ; Maynard AD ; Nicholls A ; Zimmer, Anthony T.
• Description:
  The surface structure and chemistry of ultrafine aerosol particles (typically particles smaller than 100 nm in diameter) play key roles in determining physical and chemical behavior, and is relevant to fields as diverse as nanotechnology and aerosol toxicity. Analytical scanning transmission electron microscopy (STEM) is one of the few analytical methods available that is potentially capable of characterizing ultrafine particles at subnanometer resolution. We propose a method that enables STEM to characterize and quantify elemental surface enrichment within radially symmetrical particles at a spatial resolution of less than 1 nm when used in conjunction with electron energy loss spectroscopy (EELS) and X-ray energy dispersive spectroscopy (EDS). Although the method relies on a number of assumptions for complete particle characterization, estimation of the depth of an outer layer of elemental enrichment should be possible with relatively few assumptions. A preliminary investigation of the method has been carried out using particles from gas metal arc welding on mild steel. Using the analysis method, we were able to characterize Si and O enrichment in a number of particles. Two particles were investigated extensively using EELS and EDS analysis. Both techniques allowed surface enrichment of Si to be identified and quantified in the particles, although the relatively poor sensitivity of EDS was a limiting factor in the analysis. EELS allowed rapid data collection and enabled surface enrichment of Si and O to be characterized. Using a simple model to describe elemental composition with radial position, it was estimated that Si and O were enriched in an outer layer around the particle approximately 1 nm deep. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Health Safety
• Keywords:
  Aerosol-particles Analytical-methods Analytical-processes Microscopy Models Nanotechnology Surface-properties
• ISSN:
  0278-6826
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Illinois ; Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  365-381
• Volume:
  38
• Issue:
  4
• NIOSHTIC Number:
  nn:20026126
• Citation:
  Aerosol Sci Technol 2004 Apr; 38(4):365-381
• Federal Fiscal Year:
  2004
• NORA Priority Area:
  Research Tools and Approaches: Exposure Assessment Methods
• Peer Reviewed:
  True
• Source Full Name:
  Aerosol Science and Technology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:eb244fb563d58b391e25537ece47e53553ba923c8a1d0831586b55d6d0882718af725eb2b9c9553fee410c67ee0c17fe19531f100ef196b8c5d24dea4238cf5f
• Download URL:
  https://stacks.cdc.gov/view/cdc/197198/cdc_197198_DS1.pdf
• File Type:
  [PDF - 10.52 MB ]