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 40: 8 μm*

The classic general purpose ashless filter paper with medium speed and retention.

Typical applications include gravimetric analysis for numerous components in cements,clays, iron, and steel products; as a primary filter for separating solid matter from aqueous extracts in general soil analysis; quantitative determination of sediments in milk, and as a pure analytical grade clean-up filter for solutions prior to AA
spectrometry.

Also used as a high-purity filter in the collection of trace elements and radionuclides from the atmosphere.