Filter Paper
Filter Paper
Qualitative and quantitative filter papers for the clarification and purification of samples for analysis. Available in a range of sizes, counts, grades, and formats such as circles and sheets, they are often made from cellulose or nylon.
Filter papers are familiar laboratory consumables often used with a conical funnel or similar device to filter and retain solids, particulates, and other materials from aqueous solutions, suspensions, solvents, and other liquids. Filter papers may be manufactured from natural cellulose, nylon, or glass or quartz fibers. They are typically available as pre-cut circles of various diameters, which may be folded into pleats, quadrants, or pyramids. Some filter papers are also sold as sheets or rolls that can be cut to size as needed.
Filter papers may be categorized as qualitative or quantitative. Qualitative filter papers are used for general purpose filtration applications where subsequent analysis is not critical. Quantitative filter papers (ashless papers) are intended for more exacting analytical work and may be weighed or otherwise processed after use. They are made from low-linting fibers that are typically acid-hardened during their manufacture to provide high wet strength and chemical resistance, and are pre-rinsed with demineralized water for extra purity.
Most filter papers are also graded numerically according to pore size, which in turn infers other parameters such as flow rate, retention, thickness, weight, and burst strength, that constrain and prescribe their application.
What is Filter Paper Used for?
• General applications: research laboratories, clinics, and educational settings
• Analytical applications: precipitant and particulate removal prior to further analysis or assay
• Industrial applications: foods and beverages, cosmetics, and gravimetric analysis of cements, clays, and iron and steel products
• Environmental applications: water, soil, or atmospheric sample analysis
Cytiva Grade 802 Qualitative Filter Papers
Offers fast filtration and high loading capacity for analysis involving coarse particles or gelatinous precipitates. Whatman™ Grade 802 Qualitative Filter Papers are prepleated, wet-strengthened filters for use with a conical filter funnel in routine, repetitive qualitative applications.

Cytiva Whatman™ Qualitative Filter Paper: Grade 5 Circles
Retains the fine precipitates encountered in chemical analysis. Whatman™ Qualitative Filter Paper - Grade 5 Circles are excellent clarifying filters for cloudy suspensions and for water and soil analysis.

Cytiva Whatman™ Grade 2V Folded Qualitative Filter Papers

Saves time required to fit circles into conical funnels. Whatman™ Grade 2V Folded Qualitative Filter Papers provide medium flow and nominal particle retention rating of 8µm at a higher filtration speed.

Cytiva Whatman™ Qualitative Filter Paper: Grade 4 Circles
Filters and retains course particles for monitoring air pollution. Whatman™ Qualitative Filter Paper: Grade 4 Circles are used when high flow rates in air pollution monitoring are required and the collection of fine particles is not critical.

Cytiva Whatman™ Reeve Angel 202 Creped Qualitative Circles
For routine, noncritical laboratory filtration applications such as general chemistry, pharmacology, emulsions, petroleum testing, soaps and detergents

Cytiva Whatman™ Quantitative Filter Paper: Grade 41 Circles
Use for quantitative air pollution analysis as a paper tape for impregnation when determining gaseous compounds at high flow rates or for quantitative air pollution analysis. Whatman™ Quantitative Filter Paper: Grade 41 Circles are commonly used in preparing samples for metal analysis after nitric acid digestion.

Cytiva Whatman™ Quantitative Filter Paper: Grade 541 Circles
Recommended when fast filtration of a gelatinous precipitate for gravimetric analysis is performed on a strongly acidic or alkali solution. Whatman™ Quantitative Filter Paper: Grade 541 Circles are acid hardened cellulose filters, which reduces ash to an extremely low level.

Cytiva Whatman™ Quantitative Filter Paper: Grade 50 Circles
Enables strong retention for very fine crystalline precipitates. Whatman™ Quantitative Filter Paper: Grade 50 Circles withstand shredding, wet handling, and precipitate removal by scraping.

Cytiva Whatman™ Reeve Angel 226 Creped Qualitative Circles

A general qualitative filter with creped surface. High filtration speed, faster than grade 202 and retain coarse particles gelatinous precipitates.
