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Quantitative Filter Papers - Hardened Low Ash Grades
Home | Filter Papers | Cellulose Filters | Quantitative Filter Papers - Hardened Low Ash Grades

The maximum ash content of these grades is intermediate between ashless and qualitative grades. They are particularly suitable for Büchner filtrations where it is desirable to recover the precipitate from the filter surface after filtration. Other characteristics include high wet strength and chemical resistance which are similar to the acid hardened ashless filter papers.

Grade 50: 2.7 µm
Retention of finest crystalline precipitates. The thinnest of all Whatman filter papers. Slow flow rate. Hardened and highly glazed surface. This finish also keeps the paper free from loose surface fibers. Highly suitable for qualitative or quantitative filtrations requiring vacuum assistance on Büchner or 3-piece filter funnels. Very strong when wet. Will withstand wet handling and precipitate removal by scraping. In the electronics industry, the virtual absence of fiber shedding is utilized in carriers for integrated circuits.
This grade is also available in Smear Tab format for wipe testing (e.g. testing of surfaces for radionuclide contamination).
 

Hardened Low Ash Grades

Grade 52: 7 µm
The general purpose hardened filter paper with medium retention and flow rate. Very hard surface.

Grade 54: 22 µm
Very fast filtration for use with coarse and gelatinous precipitates. High wet strength makes this grade very suitable for vacuum assisted fast filtration of ‘difficult’ coarse or gelatinous precipitates.

Typical Properties - Quantitative Hardened Low Ash Grades
Grade Description Particle
Retention
in Liquid (µm)		 Filtration
Speed
Herzberg (s)		 Ash
Content+		 Typical
Thickness
(µm)		 Basis Weight
(g/m2)
50 Slow 2.7* 2685 0.015 115 97
52 Medium 7* 235 0.015 175 101
54 Very fast 22* 39 0.015 185 92


+ Ash is determined by ignition of the cellulose filter at 900 °C in air
* Particle Retention Rating at 98% efficiency
Ordering Information - Quantitative Filter Papers - Hardened Low Ash Grades
Catalog Number Description

Grade 50
1450-042 Grade 50 Circles, 42.5 mm 100/pk
1450-050 Grade 50 Circles, 50 mm 100/pk
1450-055 Grade 50 Circles, 55 mm 100/pk
1450-070 Grade 50 Circles, 70 mm 100/pk
1450-090 Grade 50 Circles, 90 mm 100/pk
1450-110 Grade 50 Circles, 110 mm 100/pk
1450-125 Grade 50 Circles, 125 mm 100/pk
1450-150 Grade 50 Circles, 150 mm 100/pk
1450-185 Grade 50 Circles, 185 mm 100/pk
1450-240 Grade 50 Circles, 240 mm 100/pk
1450-320 Grade 50 Circles, 320 mm 100/pk
1450-400 Grade 50 Circles, 400 mm 100/pk
1450-500 Grade 50 Circles, 500 mm 100/pk
1450-561 Grade 50 Circles, 609.6 mm 100pk
1450-880 Grade 50 Sheets, 10 x 10 inches 100/pk
1450-916 Grade 50 Sheets, 150 x 230 mm 100/pk
1450-925 Grade 50 Sheets, 400 x 400 mm 100/pk
1450-900 Grade 50 Sheets, 410 x 400 mm 100/pk
1450-917 Grade 50 Sheets, 460 x 570 mm 100/pk
1450-993 Grade 50 Sheets, White Smear Tab 100/pk

Grade 52
1452-070 Grade 52 Circles, 70 mm 100/pk
1452-090 Grade 52 Circles, 90 mm 100/pk
1452-110 Grade 52 Circles, 110 mm 100/pk
1452-125 Grade 52 Circles, 125 mm 100/pk
1452-150 Grade 52 Circles, 150 mm 100/pk
1452-240 Grade 52 Circles, 240 mm 100/pk
1452-923 Grade 52 Sheets, 400 x 450 mm 500/pk

Grade 54
1454-055 Grade 54 Circles, 55 mm 100/pk
1454-070 Grade 54 Circles, 70 mm 100/pk
1454-090 Grade 54 Circles, 90 mm 100/pk
1454-110 Grade 54 Circles, 110 mm 100/pk
1454-125 Grade 54 Circles, 125 mm 100/pk
1454-150 Grade 54 Circles, 150 mm 100/pk
1454-185 Grade 54 Circles, 185 mm 100/pk
1454-240 Grade 54 Circles, 240 mm 100/pk
1454-320 Grade 54 Circles, 320 mm 100/pk
1454-500 Grade 54 Circles, 500 mm 100/pk
1454-917 Grade 54 Sheets, 460 x 570 mm 100/pk

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