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    Ashless Filter Paper

    Our Ashless Filter Papers are made under the strictest conditions using high quality raw materials. The ashless filter paper grades are made with 100% cotton linter fibres. Cellulose fibres in their natural state contain small quantities of organic and inorganic impurities. As quantitative analysis requires a high purity, these papers have been washed out with acid and finally cleaned with demineralised water to provide an ash content of 0.007%. The papers also become highly resistant to the moist state. These standard ashless grades are very pure filters suitable for routine quantitative gravimetric techniques and in the preparation of samples for use in analysis involving instrumental techniques. Because of all this, these filters are especially suitable for filtration with Buchner funnels in quantitative analysis since they meet the requirements of international standards with regards to ash content. Johnson Test Papers offers a complete range of Ashless Quantitative Cellulose Filter Papers with a choice of pore size, filtration speeds, and filter thicknesses. They are available in different filter sizes from small circle formats to large sheets. We can also make custom sized filters to meet your specific needs.


    Click on a Grade to find out more...

    Grade 351

    - Very Slow Filtering
    Application :

    Fine pores used for extremely difficult filtration conditions such as cold barium sulphate, metastannic acid, cuprous oxide.

    Grade 352

    - Medium Filtering
    Application :

    Medium pore filter paper used for fine precipiates, such as magnesium ammonium phosphate, calcium oxalate, magnesium ammonium arsenate and coarser forms of barium sulphate

    Grade 353

    - Medium fast filtering
    Application :

    Most commonly used grade for coarser precipitates such as lead, iron and silver sulphide, alkali carbonates, lead chromate, arsenic, antimony, cadmium and foodstuffs.

    Grade 354

    - Fast Filtering
    Application :

    Wide pore filter paper used for coarse and voluminous precipitates such as iron, aluminium and chromium hydroxides, Si-determination in steel and pig iron analysis.

    Available Grades
    Grade Whatman Equivalent Speed Thickness (mm) Pore Size (μM) Weight (g/m²) Filtration Speed (sec*) Burst Strength (kg/cm²)
    Grade: 351 Whatman Equivalent: = No.42 Speed: Very Slow Filtering Thicness (mm): 0.14 Pore size: 2-3 Weight: 84 Filtration speed (sec*): 180 Burst strength (kg/cm²): > 0.20
    Grade: 352 Whatman Equivalent: = No.40 Speed: Medium Filtering Thicness (mm): 0.15 Pore size: 3-5 Weight: 84 Filtration speed (sec*): 100 Burst strength (kg/cm²): > 0.20
    Grade: 353 Whatman Equivalent: = No.43 Speed: Medium fast filtering Thicness (mm): 0.16 Pore size: 5-8 Weight: 84 Filtration speed (sec*): 50 Burst strength (kg/cm²): < 0.20
    Grade: 354 Whatman Equivalent: = No.41 Speed: Fast Filtering Thicness (mm): 0.17 Pore size: 8-12 Weight: 84 Filtration speed (sec*): 20 Burst strength (kg/cm²): > 0.20