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Whatman No 1 filter papers- why are they so frequently used?

Whatman No 1 filter paper is made of cellulose fibres for routine applications with medium retention and flow rate:

The Technical Bit

Grade known as: Whatman No 1

Diameter of circles available: [mm] 10, 15, 20, 25, 30,  32, 42, 47, 55, 70, 85, 90, 110, 125, 150, 185, 240, 270, 320, 400, 500

Packs of sheets of No 1: 2.6×3.1cm, 7.5x10cm, 46x57cm, 58x68cm, 60x60cm,

Reels of No.1: 47cm wide x 100M long

Typical particle retention time: 11µm

Nominal thickness: 180µm

Typical flow rate: 57ml/min

Base weight: 87g/m2

Nominal air flow rate: 13s/100ml/in2

Material: Cellulose

Trace element levels:  Aluminium 3.6 µg/g Antimony <0.5 µg/g Arsenic <0.5 µg/g Barium <0.5 µg/g Boron <1 µg/g Calcium 27.5 µg/g Chromium 1 µg/g Copper 0.9 µg/g Iron 13.7 µg/g Lead <0.5 µg/g Magnesium 21 µg/g Manganese <0.5 µg/g Mercury <0.5 µg/g Potassium 6.2 µg/g Silicon 8.8 µg/g Sodium 32.3 µg/g Zinc 58.3 µg/g


Routine filtering with medium flow and retention rates. Commonly used for clarifying liquids. This grade is also used for qualitative analytical separations for precipitates like lead sulphate, calcium oxalate and calcium carbonate.

In agriculture it is used for soil analysis and seed testing procedures. In food and drink to separate solid foodstuffs from liquid, and is widely used in education for teaching analytical separation techniques.

Whatman No 1 Circles

Whatman No 1 is also available as folded circles known as Whatman 1V. It is available in the following sizes:

Whatman IV pre-pleated papers

12.5, 15, 18.5, 24, 27 and 32 cm pre-pleated for use in conical filter funnels

Camlab choice equivalent of Whatman No 1 is grade 601 I the same sizes and specification. If you are not sure if this filter paper is suitable for you we have a quick guide which compares all qualitative filter papers in the ranges of both Whatman and Camlab Own brand filters.

If you need a complete filtration system we have put together all the components required in one bundle package for vacuum filtration: you will also need to order 7cm cellulose filter circles to go with this bundle.