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Sample Preparation for Microscopic Particle Counting

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Direct particle counting on a MilliporeSigma filter is a simple and rapid solution for contamination analysis. After passing the sample through the membrane, examine the filter directly with incident light or render it transparent so that you can apply transmitted light. The filter is placed on the movable stage of a microscope with the contaminant side up. It is slowly traversed back and forth. As particles come into the field of view, they are counted in several discrete size ranges.

Direct particle counting on a filter is a simple and rapid solution for contamination analysis

Advantages of On-Filter Particle Counting Using Microscopy

  • Determine the size distribution of particles
  • Detect large particles or fibers easily
  • Identify particles to locate sources of contamination
You can vary the procedure to accomplish your specific goals. When you are only interested in very large particles (>150 μm), you can be less careful about cleaning your equipment. If appropriate, save time by counting particles down to 50 or 100 μm rather than down to 2 or 5 μm, since such procedures are adequate in many instances. In all particle counting procedures, adequate illumination, well-aligned optics and careful operator training are necessary.

Membranes for Particle Monitoring

Devices for Particle Monitoring

View all products for particle monitoring sample collection, preparation and analysis on our particle monitoring website.