Laboratory Products - Quantitative Paper Filters

Quantitative Paper Filters

Quantitative Filters are acid washed and are suitable for gravimetric and other critical analysis where background contamination is undesirable.

• QN 5A. (Whatman Eqv. 41) Fast flow rate, general purpose filter. This is a double acid washed paper suitable for the retention of coarse particles and gelatinous precipitates. Recommended for filtering hydroxides and metallic aerosols and determining silica content in steels. Also used in quantitative air pollution analysis and foodstuffs analysis.
• QN 5B. (Whatman Eqv. 40) Medium flow rate, general purpose filter. This product has been subjected to a double acid wash in HCI and has good chemical resistance and wet strength. Suitable for quantitative analysis of soils fertilizers, cement and minerals. Also used in the collection of trace elements and radionucleotides from the atmosphere.
• QN 5C. (Whatman Eqv. 44) Slow flow rate. High retention filter for critical gravimetric analysis and separation of precipitates that tend towards colloidal dispersion.
• QN 7. Medium flow rate. This is the highest purity quantitative paper available. Suitable for analyses of minute trace and precious metals and for research laboratories where precision is a high priority.
• QN 4A. Very slow flow rate. This acid washed paper is futher treated with nitric acid to harden the paper for superior wet strength and eliminate shedding of fibers. It has excellent pH and chemical resistance. Suitable for retaining fine crystalline particulate and use under pressure.

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