Sartorius Grade 391 is a very slow, fine-pore quantitative filter paper for retaining very fine crystalline precipitates in analytical and gravimetric work. The folded, wet-strengthened paper is made from acid-washed cotton linters with more than 98% alpha-cellulose and is designed for ash-free filtration. It can be used for pressure or vacuum filtration and for clarification and sample preparation workflows.

Key Features

Fine-pore, dense construction with a 2–3 µm retention rate.
Wet-strengthened for liquid filtration.
Made from 100% cotton linters with more than 98% alpha-cellulose.
Ash content of no more than 0.01% according to DIN 54370.
Blue-dot color coding identifies very slow, fine-pore filtration.

Applications

Analytical sample preparation and particle analysis.
Quantitative and gravimetric analysis involving very fine crystalline precipitates.
Clarification and filtration under pressure or vacuum.

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