Filter selection chart
Cellulose filter papers
Highly purified paper, almost 100% cellulose fibre. Most manufacturers give the
Whatman
equivalent reference number for their filter papers. Hover over table contents for more info, or visit
Whatman
for full details.
| Speed \ Type
| Qualitative
| Ashless
| Hardened
| Hardened
ashless
|
Fast
| 4
| 41
| 54
| 541
|
Moderately fast
| 1
| 43
|
|
|
Medium
| 2
| 40
| 52
| 540
|
Slow
| 5
| 42
44
| 50
| 542
|
Ash
| 0.06 %
| 0.007 %
| 0.015 %
| 0.006 %
|
Glass fibre filter papers
Expensive, but necessary for aggressive solutions or finer particle retention. Visit
Whatman
for full details.
| Grade
| Speed
| Pore size
/ μm
|
| GF/A
| medium
| 1.6
|
| GF/B
| very slow
| 1.0
|
| GF/C
| slow
| 1.2
|
| GF/D
| fast
| 2.7
|
Sintered glass discs
The following table refers to Pyrex sinters.
Hover over the porosity number for typical applications.
| Porosity
| Speed
| Pore size
/ μm
|
| 0
| very fast
| 160 - 250
|
| 1
| fast
| 100 - 160
|
| 2
| fairly fast
| 40 - 100
|
| 3
| general purpose
| 16 - 40
|
| 4
| slow
| 10 - 16
|
| 5
| very slow
| 4 - 10
|
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