Whatman quantitative filters are designed for gravimetric analysis and the preparation of samples for instrumental analysis. They are available in three formats designed to meet your specific needs.

Ashless: 0.007% ash maximum for Grades 40 to 44 and a maximum of 0.01% for the 589 Grades - very pure filters suitable for a wide range of critical analytical filtration procedures.

Hardened low ash: 0.015% ash maximum - treated with a strong acid to remove trace metals and produce high wet strength and chemical resistance. These filters are particularly suitable for Büchner filtration where the tough smooth surface of the filter makes it easy to recover precipitates.

Hardened ashless: 0.006% ash maximum - acid hardened to give high wet strength and chemical resistance with extremely low ash content. The tough surface makes these filters suitable for a wide range of critical filtration procedures.

Grade 41: 20 μm (fast filter paper)
The fastest ashless filter paper, recommended for analytical procedures involving coarse particles or gelatinous precipitates (e.g., iron or aluminum hydroxides). Also used in quantitative air pollution analysis as a paper tape for impregnation when determining gaseous compounds at high flow rates.

Field of Use : For internal research use only. Products are not intended for diagnostic use or resale.

Whatman is a registered trademark of Cytiva