Ahlstrom 6090-1500 Qualitative Filter Paper, Grade 609, 150 mm, 100/pk

Grade 609 qualitative filter paper is commonly used for routine laboratory separations, liquid clarification, and analytical workflows that require reliable particle removal. It is also widely referenced in beverage and protein analysis applications where low contamination is important.

This grade offers approximately 4 µm particle retention with a medium filtration speed, providing a balanced combination of throughput and retention for general laboratory use.

The product features a 150 mm diameter, Grade 609 cellulose media, and a typical filtration speed of about 98 sec/100 mL, supplied in packs of 100 sheets.

Grade 609 provides a middle-ground performance profile—faster than fine-retention grades but with better particle capture than very fast papers. This makes it a versatile choice for routine qualitative analysis and general lab filtration tasks.

Standard qualitative filter papers like Grade 609 are primarily intended for gravity filtration and quadrant-fold applications. For vacuum filtration or wet handling, laboratories often choose wet-strengthened or hardened grades for improved durability.