Particle Identification (ID)


WOHL geologists have received special training in the identification of particles in air, wipe and bulk samples. Utilizing optical, FTIR and scanning/transmission electron microscopy, complex mixtures of particles can be characterized.

Contact the laboratory for sampling instructions or to discuss the applicability of this methodology to your particular sampling scenario.

Levels of Analysis:

  1. Full Characterization Microscopic Particle ID lists all the identifiable particle types present with estimated percent of each particle type, if possible.
  2. Single Component Microscopic Particle ID reports the occurrence in a sample of ONE particle type, as indicated by the submitter. For example, clients may ask whether coal dust is present.

Methods of Dust Collection

  1. The most preferable method is to gather about a cubic inch of loose dust into a sealed container.
  2. To collect settled dust thinly dispersed across a surface, attach a 6-inch length of tubing to the INLET port of a 37 mm AA MCEF or yellow-banded 37 mm PVC filter cassette. Attach the pump to the outlet port of the cassette as usual. Vigorously rub the free end of the tubing along the surface to collect as much dust as possible. The cassette becomes a BULK dust-collection container. Collect as much dust as possible.
  3. A less preferable method of dust collection is by dabbing a length of TRANSPARENT scotch-type tape on the surface where dust has settled until the tape is loaded with dust. Attach the tape to a glass microscope slide or the inside of a thick-walled, ziplock plastic bag. DO NOT FOLD THE TAPE!
  4. Thinly dispersed dust can be collected by wiping a DRY WIPE medium along a surface where dust is settled. 4″ Whatman filter circles can be obtained from WOHL for this. Load the wipe as heavily as possible. Then, fold the filter in half and put it in a sealed container. DO NOT WET OR DAMPEN THE FILTER!

The sample is analyzed by Polarized Light Microscopy and/or Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis. This method can identify particles in house, road or foundry dust, lint, furnace filters, sediments, airborne or settled dust, stack emissions and more. Samples not appropriate for particle ID include: stains on fabric, liquids, sludge, sewage, oils and solvents.