- Counting Methods aid in micromeritics, ensuring accuracy in particle size analysis.
- Counting Methods are techniques to determine particle numbers in dispersions and powders.
- These determine size by counting individual particles and measuring them directly.
Microscopy
- Optical Microscopy:
- Suitable for particles in the 1–100 µm range.
- A small amount of sample is spread on a slide, and particle diameters are measured using a calibrated eyepiece micrometer.
- Gives information about particle size and shape.
- Electron Microscopy (SEM/TEM):
- For nanoparticles and sub-micron particles.
- Provides detailed images and accurate measurement.
Advertisements
Advantages:
- Direct visualization of particles.
- Can assess particle shape and aggregation.
Limitations:
- Time-consuming.
- Not statistically representative for very large populations.
Advertisements
Coulter Counter (Electrical Sensing Zone Method)
- Suitable for particles in 0.5 to 400 µm.
- Particles suspended in electrolyte pass through a small aperture.
- Each particle displaces electrolyte, changing electrical resistance.
- The amplitude of change is proportional to the particle volume.
Advantages:
- Provides number-based
- High accuracy and speed.
Advertisements
Limitations:
- Requires conductive liquid.
- Sensitive to air bubbles and particle shape.
