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Qualitative filter papers

Cellulose filters
> Qualitative filters
Qualitative filter papers
These cellulose filters are used in qualitative analytical techniques to determine and identify materials. Prepleated qualitative filters are also available, which give improved flow rate and increase loading capacity compared to equivalent flat filters. 

In addition, Whatman offers wet strengthened qualitative filters which contain a small quantity of a chemically stable resin to give improved high wet strength. This does not introduce any significant impurities into the filtrate. The resin, however, does contain nitrogen so these grades should not be used in Kjedldahl. All wet-strengthened grades are available in prepleated forms. Whatman provides a wide range of Qualitative Filters to meet your specific needs.

Qualitative Filter Papers - Standard Grades

Grade 1: 11µm
The most widely used filter paper for routine applications with medium retention and flow rate. Extended range of sizes includes 10mm to 500mm diameter circles and 460mm x 570mm sheets. This filter is also available in the Whatman FilterCup™. This is a convenient, disposable 70mm filter funnel with a 250mL capacity moulded from polypropylene with an integral, heat bonded filter.

This grade covers a wide range of laboratory applications and is frequently used for clarifying liquids. Traditionally the grade is used in qualitative analytical separations for precipitates such as lead sulphate, calcium oxalate (hot) and calcium carbonate.

In agriculture, it is used for soil analysis and seed testing procedures. In the food industry, Grade 1 is used for numerous routine techniques to separate solid foodstuffs from associated liquid or extracting liquid and is widely used in education for teaching simple qualitative analytical separations.

In air pollution monitoring, using circles or rolls, atmospheric dust is collected from airflow and the stain-intensity measured photometrically. For gas detection, the paper is impregnated with a chromogenic reagent and colour formation quantified by optical reflectance.

Grade 2: 8µm 
Slightly more retentive than Grade 1 with a corresponding increase in filtration time (i.e., slightly slower filtration speed). More absorbent than Grade 1. Also available in folded (prepleated) form as Grade 2V. In addition to general filtration in the 8µm particle size range, the extra absorbency is utilized, for example, to hold soil nutrient in plant growth trials. Also used for monitoring specific contaminants in the atmosphere and in soil testing.

Grade 3: 6µm 
Double the thickness of Grade 1 with still finer particle retention and excellent loading capacity; more precipitate can be held without clogging. The extra thickness gives increased wet strength and makes this grade highly suitable for use in Büchner funnels. The high absorbency is particularly valuable when the paper is used as a sample carrier. This filter is also available in the Whatman FilterCup. This is a convenient, disposable 70mm filter funnel with a 250mL capacity moulded from polypropylene with an integral, heat bonded filter.

Grade 4: 20-25µm 
Extremely fast filtering with excellent retention of coarse particles and gelatinous precipitates such as ferric hydroxide and aluminium hydroxide. Very useful as a rapid filter for routine cleanup of biological fluids or organic extracts during analysis. Used when high flow rates in air pollution monitoring are required and the collection of fine particles is not critical.

Grade 5: 2.5µm 
The maximum degree of fine particle filtration in the qualitative range. Capable of retaining the fine precipitates encountered in chemical analysis. Slow flow rate. Excellent clarifying filter for cloudy suspensions and for water and soil analysis.

Grade 6: 3µm 
Twice as fast as Grade 5 with similar fine particle retention. Often specified for boiler water analysis applications.

Cellulose filters
> Wet Strengthened Filters

Qualitative Filter Papers - Wet Strengthened Grades

These extremely strong filter papers have a high wet strength due to the addition of a small quantity of chemically stable resin. Normal qualitative applications will not introduce any significant impurities into the filtrate. The resins do, however, contain nitrogen so these grades should not be used in Kjeldahl estimations, etc. All wet-strengthened grades are available in folded (prepleated) forms.

Grade 91: 10µm
A general-purpose crêped filter for less critical routine analysis. Widely used to assay sucrose in cane sugar and within pharmaceutical laboratories for routine filtration.

Grade 113: 30µm Ultra high loading capacity with a particle retention making it ideal for use with coarse or gelatinous precipitates. Fastest flow rate of the qualitative grades. Creped surface. Thickest filter paper in the Whatman range. This filter is also available in the Whatman FilterCup. This is a convenient, disposable 70mm filter funnel with a 250mL capacity moulded from polypropylene with an integral, heat bonded filter.

Grade 114: 25µm
Only half the thickness of Grade 113 and suitable for coarse or gelatinous precipitates. Smooth surface for easy recovery of precipitates.

Cellulose filters
> Prepleated Filters

Qualitative Filter Papers - Folded (Prepleated Grades)

Time-saving Whatman qualitative grades are offered in this convenient form, which have major advantages over flat circles:

  • Savings in time required to quadrant-fold circles to fit conical filter funnels in repetitive or multiple analysis
  • Decreased overall filtration time because of the extra surface area exposed; the normal slow down of filtration speed due to the loading of particulate is postponed
  • Increased total loading capacity because more filter area is available
  • Maintained flow rate because of the reduction in filter paper contact with funnel side and, of course, the self-supporting shape of the filter itself
  • The prepleating does not significantly affect any of the technical data and the same figures may be used for the flat circles.

Grade 2V: 8µm
Widely used for general purpose filtration. Slightly more retentive than No. 1. Has excellent particle retention and a good filtration speed and loading capacity.

Grade 113V: 30µm
Very thick and strong filter with creped surface for extremely high loading capacity, particularly in folded form. Fastest flow rate of any qualitative grade. Ideal for coarse particles and gelatinous precipitates.

Grade 114V: 25µm
Strong filter with very fast flow rate. Ideal for coarse particles and gelatinous precipitates. Smooth surface.

Qualitative Filter Papers - Student Grade/Grade 93

Designed for educational use, this filter paper is intermediate in speed and retention between Grades 1 and 4. Student grade retains those flocculent and medium precipitates most often encountered in student experiments.

Available in a dispenser pack, it can be attached to the wall or bench, placed on a shelf either upright or flat, and used as a normal carton or as a convenient dispenser. The envelopes are released individually for easy one-at-a-time removal. Package and envelopes are clearly marked for size and content.

Standard Circle Filter Funnel Volumes
The maximum practical volume of the most popular disc sizes (quadrant folded) are:
Diameter (mm) Volume (mL)
90 15
110 20
125 35
150 75
185 135
240 300
Ordering Information - Qualitative Standard Filter Circles
  Catalogue Number  
Diameter (mm) Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 Grade 6 Quantity/Pack
10 1001-6508 500
23 1003-323 100
25 1001-325 1004-325 1005-325 100
30 1001-329 100
32 1001-032 100
42.5 1001-042 1002-042 1003-042 1004-042 1005-042 1006-042 100
47 1001-047 1004-047 1005-047 100
55 1001-055 1002-055 1003-055 1004-055 1005-055 100
70 1001-070 1002-070 1003-070 1004-070 1005-070 1006-070 100
85 1001-085 100
90 1001-090 1002-090 1003-090 1004-090 1005-090 1006-090 100
110 1001-110 1002-110 1003-110 1004-110 1005-110 1006-110 100
125 1001-125 1002-125 1003-125 1004-125 1005-125 1006-125 100
150 1001-150 1002-150 1003-150 1004-150 1005-150 1006-150 100
185 1001-185 1002-185 1003-185 1004-185 1006-185 1006-185 100
240 1001-240 1002-240 1003-240 1004-240 1006-240 1006-240 100
270 1001-270 1002-270 1004-270 100
320 1001-320 1002-320 1003-320 1004-320 1005-320 100
385 1001-385 1002-385 100
400 1001-400 1004-400 100
500 1001-500 1002-500 1003-500 100
FilterCup 70**** 1600-001 1600-003 25
Ordering Information - Qualitative Wet Strengthened Filter Circles
  Catalogue Number  
Diameter (mm) Grade 91 Grade 93/Student Grade 113 Grade 114 Quantity/Pack
90 1113-090 1114-090 100
110 1091-110* 1093-111** 1113-110 100
125 1091-125* 1093-126** 1113-125 1114-125 100
150 1091-150*** 1113-150 1114-150 100
185 1091-185*** 1113-185 1114-185 100
190 1091-190 100
240 1091-240*** 1113-240 1114-240 100
270 1114-270 100
320 1113-320 100
400 1114-400 100
500 1113-500 100
FilterCup 70**** 1600-113 25

* Packed in 4000 subdivided into 100. 
** Packed in 50 envelopes of 25 circles each. 
*** Packed in 1000 subdivided into 100. 
**** FilterCup Stem with Stopper - one time purchase - Catalogue Number 1600-900
Ordering Information - Qualitative Filter Circles Folded (pleated)
  Catalogue Number  
Diameter (mm) Grade 2V Grade 113V Grade 114V Quantity/Pack
125 1202-125 1213-125 1214-125 100
150 1202-150 1213-150 1214-150 100
185 1202-185 1213-185 1214-185 100
240 1202-240 1213-240 1214-240 100
270 1202-270 1213-270 100
320 1202-320 1213-320 1214-320 100
385 1202-385 100
400 1202-400 100
500 1202-500 1213-500 100
Ordering Information - Qualitative Standard Filter Sheets
Dimensions (mm) Catalogue Number Quantity/Pack
Grade 1
460 x 570 1001-917 100
460 x 570 1001-918 500
580 x 680 1001-931 100
Grade 2
460 x 570 1002-917 100
580 x 680 1002-931 100
Grade 3
460 x 570 1003-917 100
Grade 4
460 x 570 1004-917 100
Ordering Information - Qualitative Filter Paper
  Catalogue Number  
Diameter (mm) Grade 595 Grade 597 Grade 598 Grade 602 h Quantity/Pack
12.7 10 311 862 1000
42.5 10 312 040 100
45 10 311 804 100
55 10 311 807 100
70 10 311 808 100
90 10 311 809 10 312 209 10 312 609 100
110 10 311 610 10 311 810 100
125 10 311 611 10 311 811 10 312 611 100
150 10 311 612 10 311 812 10 312 612 100
185 10 311 814 10 312 614 100
240 10 311 820 10 312 620 100
320 10 311 822 100
Diameter (mm) Grade 520 a Grade 2294 Grde 2589 a   Quantity/Pack
110 10 342 810   100
140 10 343 630   500
180 / 33 ZL1 10 342 860   100
210 / 60 ZL1 10 342 862   100
270 10 331 421   100
Diameter (mm) Grade 0048 Grade 551 Grade 3612   Quantity/Pack
32 10 348 903   1000
90 10 310 809   100
240 10 341 420   100
1Round filter with central hole
Ordering Information - Qualitative Folded (pleated) Filter Papers
  Catalogue Number  
Diameter (mm) Grade 520 a ½ Grade 595 ½ Grade 597 ½ Grade 602 h ½ Grade 2555 ½ Quantity/Pack
70 10 311 841 100
90 10 311 842 10 312 642 100
110 10 311 643 10 311 843 100
125 10 311 644 10 311 844 10 312 644 100
150 10 311 645 10 311 845 10 312 645 100
185 10 311 647 10 311 847 10 312 647 10 313 947 100
240 10 331 451 10 311 651 10 311 851 10 312 651 10 313 951 100
270 10 311 652 10 311 852 100
320 10 311 653 10 311 853 10 313 953 100
385 10 311 854 100
500 10 331 456 10 311 856 100
700 10 331 459 100
Diameter (mm) Grade 591 ½ Grade 520 b II ½ Grade 598 ½ Grade 287 ½   Quantity/Pack
125 10 312 244 10 310 244   50
150 10 310 245   50
185 10 311 347 10 312 247 10 310 247   50
240 10 311 351 10 312 251 10 310 251   50
320 10 331 653 10 310 253   50
500 10 312 256   50
Ordering Information - Qualitative Filter Paper Sheets
  Catalogue Number  
Dimensions (mm) Grade 591 Grade 595 Grade 597 Grade 598 Grade 520 a Grade 520 bII Quantity/ Pack
580 x 580 10 311 897 100
580 x 580 10 311 387 10 312 287 10 331 487 10 331 681 250
580 x 580 10 311 687 10 311 887 500
Dimensions (mm) Grade 2411 Grade 2589 a Grade 2589 c Grade 2589 d Grade 0860   Quantity/Pack
580 x 580 10 343 687 10 334 597   100
580 x 580 10 343 287   200
25 x 75 10 343 876 10 343 976   100
Dimensions (mm) Grade 0903 Grade 0905         Quantity/Pack
580 x 580 10 334 887 10 334 987         500
450 x 450 10 334 885 10 334 985         500
Ordering Information - Shark Skin Filters
Diameter (mm) Catalogue Number Quantity/Pack
110 10 347 510 100
150 10 347 513 100
290 10 347 577 100
320 10 347 530 100
812.8 10 347 576 100
Ordering Information - Shark Skin Filter Sheets
Dimensions (inches) Catalogue Number Quantity/Pack
8 x 10 10 538 877 100
26 x 53 10 347 588 500
32 x 64 10 347 530 500
37 x 37 10 538 873 500
21 x 750 feet 10 537 138 1
 
 
 

Quantitative filter papers

Cellulose filters
> Quantitative filters
Quantitative filter papers
Whatman quantitative filters are designed for gravimetric analysis and the preparation of samples for instrumental analysis. They are available in three formats designed to meet your specific needs. 
  • Ashless: 0.007% ash maximum - very pure filters ideal for a wide range of critical analytical filtration procedures.
  • Hardened low ash: 0.015% ash maximum - treated with a strong acid to remove trace metals and produce high wet strength and chemical resistance. These filters are particularly suitable for Büchner filtration where the tough smooth surface of the filter makes it easy to recover precipitates.
  • Hardened ashless: 0.006% ash maximum - acid hardened to give high wet strength and chemical resistance with extreme low ash content. The tough surface makes these filters suitable for a wide range of critical filtration procedures.

Quantitative Filter Papers - Ashless Grades (Ash 0.007%)

Grade 40: 8µm
The classic general purpose ashless filter paper with medium speed and retention. Typical applications include gravimetric analysis for numerous components in cements, clays, iron and steel products; as a primary filter for separating solid matter from aqueous extracts in general soil analysis, quantitative determination of sediments in milk and as a pure analytical grade clean-up filter for solutions prior to AA spectro- photometry. Used also as a high purity filter in the collection of trace elements and radionuclides from the atmosphere.

Grade 41: 20-25µm 
The fastest ashless filter paper, recommended for analytical procedures involving coarse particles or gelatinous precipitates (e.g., iron or aluminium hydroxides). Also used in quantitative air pollution analysis as a paper tape for impregnation when determining gaseous compounds at high flow rates. This filter is also available in the Whatman Disposable Filter Funnel. This is a convenient, disposable 47mm filter funnel with a 250mL capacity. The 47mm Grade 41 filter can be easily removed for further analysis or culturing.

Grade 42: 2.5µm 
A world standard for critical gravimetric analysis with the finest particle retention of all Whatman cellulose filter papers. Typical analytical precipitates include barium sulphate, metastannic acid and finely precipitated calcium carbonate.

Grade 43: 16µm 
Intermediate in retention between Grade 40 and 41, and twice as fast as Grade 40. Typical applications include foodstuffs analysis; soil analysis; particle collection in air pollution monitoring for subsequent analysis by XRF techniques; and inorganic analysis in the construction, mining and steel industries.

Grade 44: 3µm 
Thin version of Grade 42 retaining very fine particles but with lower ash weight per sample and almost twice the flow rate as Grade 42.

Cellulose filters
> Quantitative hardened filters

Quantitative Filter Papers - Hardened Low Ash Grades (Ash 0.015%)

The maximum ash content of these grades is intermediate between ashless and qualitative grades. They are particularly suitable for Buchner 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: 2.7µm 
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 fibres. 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 fibre shedding is utilised in carriers for integrated circuits.

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

Grade 54: 20-25µm
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.

Quantitative Filter Papers - Hardened Ashless Grades (Ash 0.006%)

These are the supreme quantitative filter papers featuring high wet strength and chemical resistance. These papers are acid hardened, which reduces ash to an extremely low level. Their tough surfaces make them suitable for a wide range of critical analytical filtration operations. Each grade offers a convenient combination of filtration speed and particle retention.

Grade 540: 8µm 
The general purpose hardened ashless filter paper with medium retention and flow rate. Extremely pure and strong with a hard surface. High chemical resistance to strong acid and alkali. Frequently used in the gravimetric analysis of metals in acid/alkali solutions and in collecting hydroxides after precipitation by strong alkalis.

Grade 541: 20-25µm 
Fast filtration of coarse particles and gelatinous precipitates in acid/alkali solutions during gravimetric analysis. Typical applications include fibre in animal foodstuffs, gelatine in milk and cream, chloride in cement, and chloride and phosphorous in coal and coke.

Grade 542: 2.7µm
High retention of fine particles under demanding conditions. Slow flow rate. Very hard and strong with excellent chemical resistance. Often used in gravimetric metal determinations.

Standard Circle Filter Funnel Volumes
The maximum practical volume of the most popular disc sizes (quadrant folded) are:
Diameter (mm) Volume (mL)
90 15
110 20
125 35
150 75
185 135
240 300
Ordering Information - Quantitative Ashless Filter Circles
  Catalogue Number  
Diameter (mm) Grade 40 Grade 41 Grade 42 Grade 43 Grade 44 Quantity/Pack
Filter Circles
30 1440-329 100
42.5 1440-042 1441-042 1442-042 100
47 1440-047 1441-047 1442-047 100
55 1440-055 1441-055 1442-055 100
70 1440-070 1441-070 1442-070 1444-070 100
90 1440-090 1441-090 1442-090 1443-090 1444-090 100
110 1440-110 1441-110 1442-110 1443-110 1444-110 100
125 1440-125 1441-125 1442-125 1443-125 1444-125 100
150 1440-150 1441-150 1442-150 1443-150 1444-150 100
185 1440-185 1441-185 1442-185 1443-185 1444-185 100
240 1440-240 1441-240 1442-240 100
320 1441-320 1442-320 100
Disposable Filter Funnel
    1920-1441       5
Filter Sheets
8" x 10" 1441-866 100
460 mm x 570 mm   1441-917 100
Ordering Information
Quantitative Hardened Low Ash Filter Circles Quantitative Hardened Ashless Filter Circles
  Catalogue Number Catalogue Number  
Diameter (mm) Grade 50 Grade 52 Grade 54 Grade 540 Grade 541 Grade 542 Quantity/Pack
21 1540-321 100
24 1540-324 100
42.5 1450-042 1540-042 1541-042 100
47 1541-047 100
55 1450-055 1454-055 1540-055 1541-055 1542-055 100
70 1450-070 1452-070 1454-070 1540-070 1541-070 1542-070 100
90 1450-090 1452-090 1454-090 1540-090 1541-090 1542-090 100
110 1450-110 1452-110 1454-110 1540-110 1541-110 1542-110 100
125 1450-125 1452-125 1454-125 1540-125 1541-125 1542-125 100
150 1450-150 1452-150 1454-150 1540-150 1541-150 1542-150 100
185 1450-185 1454-185 1540-185 1541-185 1542-185 100
240 1450-240 1452-240 1454-240 1540-240 1541-240 1542-240 100
320 1450-320 1454-320 1541-320 100
400 1541-400 100
500 1454-500 100
Surface Wipes
Smear Tab 1450-993 100
Filter Sheets
460 mm x 570 mm 1454-917 1541-917 100
Ordering Information - Quantitative Filter Paper
  Catalogue Number  
Diameter (mm) Grade 589/1 Grade 589/2 Grade 589/3 Quantity/Pack
12.7 10 300 102 1000
40.5 10 300 103 100
50 10 300 106 100
55 10 300 107 100
70 10 300 108 100
90 10 300 009 10 300 109 100
110 10 300 010 10 300 110 10 300 210 100
125 10 300 011 10 300 111 10 300 211 100
150 10 300 012 10 300 112 10 300 212 100
185 10 300 014 10 300 114 10 300 214 100
240 10 300 120 100

Cellulose filters

Ordering Information - Quantitative Folded (pleated) Filter Papers
  Catalogue Number  
Diameter (mm) Grade 589/2 ½ * Quantity/Pack
110 10 300 143 100
150 10 300 145 100
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