How Many Different Grades for Hawach Ashless Quantitative Filter Paper?

Quantitative filter paper: ashless grade
Ashless quantitative filter paper is produced under strict control with high-quality cotton lint as raw material. These high-purity filter papers are ideal products for various important analysis and filtration steps; accurate results can be obtained for gravimetric analysis.

In HAWACH, there are five grades of ashless quantitative filter papers, BIO-0, BIO-1, BIO-2, BIO-3, and BIO-4.

GradeParticle retentionSurfaceSpeedAshWet Burst
BIO-4316μmSmoothMedium to Fast<0.007%>180

Quantitative Medium Flow Filter Paper Grade: BIO-40: 8μm
It’s HAWACH Classical ashless filter paper with a wide range of uses (ash content <0.007%), with medium particle retention and flow rate, which has a wide range of applications. The typical applications include laboratory gravimetric analysis such as cement, clay, iron and steel products; atomic absorption spectrophotometry filtration of the solution before the assay, tomic absorption spectrophotometry, filtration in soil analysis, filtration in soil analysis, etc. It can also be used for high-purity filtration collection of trace elements and radioactive elements in atmospheric monitoring. One box with 100 pcs round filter papers are available.

Quantitative Ashless Filter Paper Grade: BIO-41: 20-25μm
With the largest particle retention, it’s the fastest flow ashless rate filter paper (ash content <0.007%), which is often used in the analysis of large particles such as aluminum hydroxide or ferric hydroxide or for the filtration of gel precipitates. In quantitative air pollution analysis, it can be used as an adsorbate when measuring gaseous compounds at high flow rates. One box with 100 pcs round filter papers are available.
Quantitative Laboratory Filter Paper Grade: BIO-42: 2.5μm
It’s a kind of medium-speed filter paper with the smallest retained particles in the HAWACH cellulose filter paper, a standard filter paper for the world’s evaluation of constant gravimetric analysis, and the ash content is <0.007%. It is frequently used in analysis of fine particle precipitates such as barium, metatin, and carbon calcium. One box with 100 pcs round filter papers are available.
Quantitative Roll Filter Paper Grade: BIO-43: 16μm
The retention is between BIO-40 and BIO-41 filter paper, and the filtration speed is twice that of BIO-40 filter paper, ash content <0.007%. It’s suitable for sample collection in food analysis, soil analysis, air pollution monitoring and inorganic analysis in the construction, mining, and iron and steel industries. One box with 100 pcs round filter papers are available.
Quantitative Cellulose Filter Paper Grade: BIO-44: 3μm
The ash content of BIO-44 filter paper is lower than that of other filter papers in this series, and the efficiency of collecting particles is slightly lower than that of BIO-42, but the flow rate is almost twice that of BIO-42. The round filter paper is packaged in a box of 100 pieces.

Quantitative filter paper: hardened low ash grade
For the hardened low ash grade, the ash content is between the qualitative grade and sh-free grade, with a tough and smooth surface making it easy to recover sediment. Such kind of filter paper is very suitable for Buchner funnel filtration. Other characteristics including high wet strength and chemical compatibility are similar to hardened ashless grades. There are three grades available, 2.7 μm, 7 μm, and 20-25 μm. Details are as follows:

Grade 50: 2.7 μm
As the thinnest kind of HAWACH filter paper with excellent particle retention and slow flow rate, it can retain very fine crystals and precipitates. No.50 filter paper is currently the designated standard filter paper for drilling fluid determination worldwide and is widely used in fluid laboratories for oil and gas extraction operations. In food analysis, it is combined with others to determine the fat content in meat products. It can be used in a three-piece funnel vacuum, quantitative filtration or Buchner funnel with its hardened surface preventing the fiber from falling off effectively. With very good wet strength, it can be scraped off in wet state. In the electronics industry, it is a carrier with almost no fiber shedding and is used in integrated circuits. It also provides a smear pattern for wiping tests (for example, surface tests for radionuclide contamination).

Grade 52: 7 μm
This kind of filter paper has a medium flow rate, medium retention capacity, and tough surface, which is suitable for conventional filtration.

Grade 54: 20-25 μm
This hardened low ash quantitative filter paper features high humidity and a fast flow rate. It is frequently used in colloidal precipitates filtration, like the thyl hydroxyquinine in feed and rapid vacuum filtration to remove hard-to-filter coarse particles.

BIO 541: 22μm
In addition to the above five grades, there is also a special one Grade 541 : 22μm. It’s  hardened for high wet strength and chemical resistance, such as the rapid filtration of large particles and colloidal precipitates in acidic or alkaline solutions for specific gravity analysis. The tough surface makes these filters suitable for a variety of demanding filtration steps.

Typical applications include fiber determination in animal food, gel determination in milk and cream, chloride analysis in cement, and determination of chlorine and phosphorus in coal and coke. It is also used for the determination of soybean protein in meat by enzyme-linked immunosorbent assay and the determination of ascorbic acid by titration. In terms of ambient air pollution, due to the high flow rate and extremely low chemical background of filter paper, it can be used for atmospheric particulate matter sampling and heavy metal element analysis, such as hexavalent chromium (Cr6+), lead, mercury, arsenic, copper, etc. It can also be used for fluoride, Sampling of ammonia pollutants, lead, mercury, arsenic, etc.