Scanning Electron Microscopy (SEM)
Scanning Electron Microscopy (SEM) is a high-resolution microscopic technique. In general terms, a focused beam of electrons interacts with the surface of the sample, which in turn produces secondary and backscattered electrons. The instrument’s detector(s) collect these emitted electrons and translate the signal into a high-resolution image of the sample’s surface. These vivid images of the topography of a sample’s surface can stand alone as an important source of information (e.g., general size and morphology, texture, surface variations, density, etc.) or complement the data obtained through other physical characterization analyses (e.g., particle size, porosity, BET surface area, etc.) available at PTL.
SEM is recognized by numerous standards and guidance agencies, including the ISO, ASTM, USP, and EP. This technique’s ability to generate high-resolution images of a sample has proven useful to industries including environmental, pharmaceutical, food, health, abrasives, biotechnology, biomedical devices, and beauty/cosmetic industries.
For dry/dried samples, SEM can analyze almost anything, including but not limited to active pharmaceuticals (APIs), excipients, filters, diatomaceous earth, and environmental emission samples. Common applications include QA/QC batch testing, general survey screening measurements, and comparative studies.
Advantages
- Useful for examining general size and morphology, texture, surface variations
- Capable of much higher magnification than optical microscopy
Considerations
- Particulate must be dry prior to analysis
- Can accommodate sample sizes up to 70 mm in diameter and 50 mm in height
Sample Requirements
For solid samples, the ideal sample amount is up to 500 mg.
For liquid samples, particulate must be captured and dried before analysis.
For additional questions on your sample needs, please contact us to share specifics about your sample and options for suitable sample quantities.
Detection Range
Particulate can be detected down to about 20 nanometers (nm), up to a max size of 70 mm diameter x 50 mm height (~2.75 in x ~1.96 in).
Data Reported
A typical SEM image package includes up to 8 images at increasing magnification (scale bar included on images for reference).
Instrumentation
PTL uses the JEOL Neoscope II for our Scanning Electron Microscopy (SEM) analyses.
