Filter Papers Qualitative Grade 631 Ahlstrom-Munksjö

This Ahlstrom-Munksjö qualitative laboratory filter paper is a 10 µm, Medium Speed grade used for the filtration of coarse particles and gelatinous precipitates, such as ferric, aluminium, and magnesium hydroxides. Grade 631 is used in air monitoring and gas filtration when a high flow rate is needed. This grade is also found in routine cleanup analysis of insoluble liquids such as biological fluids and organic elements.

Ahlstrom-Munksjö 631: 10 µm, Medium Speed. Equivalent to Whatman Grade 4 or 4CHR.

Ahlstrom-Munksjo Cross Reference

How to Choose the Right Filter Paper Size?

The filter paper should be about 1.5 to 1.8 times the funnel diameter.

Please note the below grid is a recommendation of what diameter filter paper is compatible with glass or plastic filter funnels.

When folded into a cone (typically in quarters), it should fit inside the funnel with about 5 to 10mm extending above the rim for easy handling.

What Is Filter Paper Used For?

Filter paper is used to separate solids from liquids or gases, acting as a semi-permeable barrier that allows certain substances to pass through while retaining others. It's commonly used in laboratories for various applications, including filtration, sample preparation, and analysis.

What Do the Grades of Filter Paper Mean?

Filter paper grades indicate the level of particle retention, though the numbering doesn't run simply from coarse to fine. Ahlstrom-Munksjö Grade 642, for example, has a finer 2 µm retention than Grade 601 (2.5 µm), while Grade 631 is considerably coarser at 10 µm. Consider the thickness of the filter paper too: thicker papers can hold more material, but they may also reduce flow rate.