Qualitative Filter Papers-Grade 5: 2.5μm

Grade 42: 2.5 μm*(Ashless Grades)

Used for critical gravimetric analysis with the finest particle retention of all
Whatman cellulose filter papers.

Typical analytical precipitates include barium sulfate, metastannic acid, and finely precipitated calcium carbonate.

Grade 50: 2.7 μm*
Retention of very fine crystalline precipitates.

The thinnest of all Whatman filter papers with a slow flow rate, these filters have a hardened and highly glazed surface, which also keeps the paper free from loose surface fibers.

Highly suitable for
qualitative or quantitative filtrations requiring vacuum assistance on Büchner
or 3-piece filter funnels.

Very strong when wet and will withstand wet handling and
precipitate removal by scraping.

In the electronics industry, the virtual absence of
fiber shedding is utilized in carriers for integrated circuits.

This grade is also available in Smear Tab format for wipe testing (e.g. testing of
surfaces for radionuclide contamination).