Quantitative (Hardened) Filter Papers

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Laboratory Filter Papers for Gravimetric Analysis and Environmental Monitoring.


Quantitative (Hardened) Filter Papers


  • 100% cotton linter cellulose.
  • Ash Content: 0.01%(Except No.4A 0.025%).
  • Acid washed: Double acid washed in hydrochloric then hydrofluoric acid (No. 3, 5A, 5B, 5C, 6), then rinsed with ultrapure water to neutralize. No. 4A is further treated with nitric acid before washing.


  • No. 3 (Ashless) Medium retention (5-10 μm),fast flow rate Analysis of soils, fertilizers, cement, and minerals.
  • No. 5A (Ashless) Fast flow rate, retains coarse particulates and gelatinous precipitates (>10 μm). Filter hydroxides and metallic aerosols, environmental monitoring, determine silica content in steel.
  • No. 5B (Ashless) Retains medium particles(5-10 μm) such as CaCO3,PbSO4, CaCO4, MnCO3,ZnCO3, ZnS, AgCl.
  • No. 5C (Ashless) Collect fine precipitates(<5 μm) such as SrSO4,BaSO4, HgCrO4, and colloidal dispersions;gravimetric analysis.
  • No. 6 (Ashless) Retains medium-fine particulates (2-10 μm), trace and precious metals.
  • No. 7 (Ashless) Highest purity for retaining medium particles (5-10 μm),precise gravimetric analysis.
  • No. 4A (Hardened)High wet strength, suitable for use under high pressure, high chemical and pH resistance,retains fine crystalline precipitates (<5 μm), slow flow.


  • Quantitative papers available in discs in the following diameters (mm): 55, 70, 90, 110, 125, 150, 185, 240, 285, 300, 330, 360, 400, 500
  • Order by specifying first the grade of filter then the diameter, e.g. (No.5A, 125 mm), (No.6, 55 mm).• Package of 100

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