Greenwood Products, Inc.

Ahlstrom Qualitative Filter Papers

Ahlstrom’s qualitative grades of filter paper are, by definition, recommended for use in analytical methods, which determine or identify particulate constituents of a mixture irrespective of the amount present. Qualitative filter papers are often used in routine separation work that still requires high purity and consistent performance. Ahlstrom offers a complete range of low ash filter papers for general laboratory work that provides you with the correct combination of particle retention, filtration speed, loading capacity and wet-strength. All our qualitative grades consist of >95% super refined a-cellulose and linter fibers.

KEY FEATURES:

Qualitative analysis
Untreated
Wet-Strengthened grades available
Low ash content 0.06%
Consistent performance
Custom cut
Bulk packaging

STANDARD GRADES (NON WET-STRENGTHENED)
Standard qualitative filter papers are suitable for quadrant folded or gravity ?ow applications. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. We do not recommend these grades for use in vacuum work or when wet handling is required.

Typical Grade Properties (Standard Grade)

Standard Grade	Retention in µm	Filtration Speed Herzberg sec/100mls	Filtration Speed Rapidity sec/100mls	Loading Capacity
610	1.5	1724	4	Medium
642	2.0	229	30	Medium
601	2.5	124	55	Medium
237	3.0	114	60	Very High
609	4.0	98	70	Medium
613	6.0	114	60	Medium
631	10.0	34	200	High
615	25.0	29	235	High
617	35.0	19	360	Very High

WET-STRENGTHENED GRADES
Qualitative wet-strengthened grades are manufactured for applications using filter paper in a system or apparatus that operates under pressure or vacuum conditions. These systems require the use of extremely strong filter paper such as those in Ahlstrom ‘s Binder Series. These grades contain a small amount of chemically stable, insoluble binding resin that strengthens the natural fiber-to-fiber bonds under wet conditions. Grades containing wood fibers or resins containing nitrogen, are not recommended for use in quantitative ashing techniques and in Kjeldahl estimations. Ahlstrom’s qualitative wet-strengthened filter papers are also used in industrial laboratories where technicians require a strong and economical filter paper with consistent quality and performance.

Typical Grade Properties (Wet-Strength Grade)

Standard Grade	Retention in µm	Filtration Speed Herzberg sec/100mls	Filtration Speed Rapidity sec/100mls	Loading Capacity
950	2.0	491	14	Medium
909	3.0	105	65	Medium
962	27.0	28	245	High
961	40.0	19	360	Very High

Qualitative Filter Catalog Numbers
(100 per box, grade numbers 237 & 617 are 50 per box)

Size	237	601	609	610	613	615	617	631	642
2.5	2370-0250	6010-0250	6090-0250	6100-0250	6130-0250	6150-0250	6170-0250	6310-0250	6420-0250
4.25	2370-0425	6010-0425	6090-0425	6100-0425	6130-0425	6150-0425	6170-0425	6310-0425	6420-0425
4.7	2370-0470	6010-0470	6090-0470	6100-0470	6130-0470	6150-0470	6170-0470	6310-0470	6420-0470
5.5	2370-0550	6010-0550	6090-0550	6100-0550	6130-0550	6150-0550	6170-0550	6310-0550	6420-0550
7.0	2370-0700	6010-0700	6090-0700	6100-0700	6130-0700	6150-0700	6170-0700	6310-0770	6420-0700
9.0	2370-0900	6010-0900	6090-0900	6100-0900	6130-0900	6150-0950	6170-0900	6310-0900	6420-0900
11.0	2370-1100	6010-1100	6090-1100	6100-1100	6130-1100	6150-1100	6170-1100	6310-1100	6420-1100
12.5	2370-1250	6010-1250	6090-1250	6100-1250	6130-1250	6150-1250	6170-1250	6310-1250	6420-1250
15.0	2370-1500	6010-1500	6090-1500	6100-1500	6130-1500	6150-1500	6170-1500	6310-1500	6420-1500
18.5	2370-1850	6010-1850	6090-1850	6100-1850	6130-1850	6150-1850	6170-1850	6310-1850	6420-1850
20.5	2370-2050	6010-2050	6090-2050	6100-2050	6130-2050	6150-2050	6170-2050	6310-2050	6420-2050
24.0	2370-2400	6010-2400	6090-2400	6100-2400	6130-2400	6150-2400	6170-2400	6310-2400	6420-2400
27.0	2370-2700	6010-2700	6090-2700	6100-2700	6130-2700	6150-0270	6170-2700	6310-2700	6420-2700
32.0	2370-3200	6010-3200	6090-3200	6100-3200	6130-3200	6150-3200	6170-3200	6310-3200	6420-3200
38.5	2370-3850	6010-3850	6090-3850	6100-3850	6130-3850	6150-3850	6170-3850	6310-3850	6420-3850
40.0	2370-4000	6010-4000	6090-4000	6100-4000	6130-4000	6150-4000	6170-4000	6310-4000	6420-4000
45.0	2370-4500	6010-4500	6090-4500	6100-4500	6130-4500	6150-4500	6170-4500	6310-4500	6420-4500
50.0	2370-5000	6010-5000	6090-5000	6100-5000	6130-5000	6150-5000	6170-5000	6310-5000	6420-5000

Qualitative Filter Cross Reference

VWR Grade	Fisher Grade	Whatman Grade	Ahlstrom Grade
-	-	1	601
-	P4	Student Grade	642
-	-	3	237
415	P8	4	615
410	P2	5	610
417	-	-	617

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