Whatman 1004-090 Filter Circles, 90mm Dia, Grade 4, 100/pk (PN:1004-090)

These filter papers are designed for general qualitative filtration, especially when fast flow rates are required. They are commonly used for routine laboratory tasks such as clarifying biological fluids, filtering organic extracts, and sample preparation.

Grade 4 refers to a standard qualitative filter paper with high flow rate and coarse particle retention. It is ideal for applications where speed is more important than capturing very fine particles.

This filter paper has a particle retention of approximately 20–25 µm, making it suitable for capturing coarse particles and gelatinous precipitates while allowing liquids to pass through quickly.

Grade 4 is best suited for samples containing larger particles, such as precipitates like ferric hydroxide or aluminum hydroxide. It is also effective for air pollution testing and general analytical separations.

These filters are made from high-quality cellulose fibers, providing consistent porosity, reliable filtration performance, and compatibility with a wide range of laboratory solutions.