Whatman* Quantitative Filter Papers, Hardened Ashless Grades (Ash 0.006%)

Grade 540: 8 µm
The general purpose hardened ashless filter paper with medium retention and flow rate. Extremely pure and strong with a hard surface. High chemical resistance to strong acid and alkali. Frequently used in the gravimetric analysis of metals in acid/alkali solutions and in collecting hydroxides after precipitation by strong alkalis.
Grade 541: 20 - 25 µm
Fast filtration of coarse particles and gelatinous precipitates in acid/alkali solutions during gravimetric analysis. Typical applications include fiber in animal foodstuffs, gelatin in milk and cream, chloride in cement and chloride and phosphorous in coal and coke.
Grade 542: 2.7 µm
High retention of fine particles under demanding conditions. Slow flow rate. Very hard and strong with excellent chemical resistance. Often used in gravimetric metal determinations.