Which filter material is specified for sampling at 0.8 micron?

• A. Glass Fiber
• B. Nylon
• C. Mixed cellulose Ester
• D. Polypropylene

Answer: (C)

Focusing on having a defined pore size that matches the target particle size is the key idea. A filter with a fixed pore size around 0.8 micron gives predictable capture for particles near that size, reducing the chances of losing particles or letting them pass through. Mixed cellulose ester membranes are available in a fixed 0.8 micron pore size, so they’re the material specified when you need to sample at that exact size. Their controlled pore structure and chemical compatibility help ensure consistent results and a clean background for analysis, which is especially important when you're assessing submicron particles. Other media—glass fiber, nylon, or polypropylene—are fibrous or have broader retention characteristics and aren’t defined by a precise 0.8 micron pore size, making them less suitable for a strict 0.8 micron specification.