Qualitative Filter Papers-Grade 5: 2.5μm

Slightly more retentive than Grade 1 with a corresponding increase in filtration time (i.e., slightly slower filtration speed).

More absorbent than Grade 1. In addition to general filtration in the 8 μm particle size range, the extra absorbency is utilized, for example, to hold soil nutrient in plant growth trials.

Also used for monitoring specific contaminants in the atmosphere and in soil testing.

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).