To List the Features and Use Notes of the Hawach Filter Papers

About Hawach

Hawach takes “focusing on life sciences and developing scientific research technology” as the central concept to provide scientists, reagents, consumables, antibodies, instruments, etc. in the fields of molecular biology, cell biology, immunology, proteomics, clinical diagnosis, etc.

Whether it is in an ordinary laboratory or a research laboratory, the filtration device is an indispensable instrument in chemical analysis, and its accuracy directly affects the test results. During the operation process, the operator first thinks of a high-precision, full-featured, and easy-to-use appliance. The following shows the features of Hawach 20 micron filter paper BIO-4, which is well-known for its high quality and reliability. Welcome to contact Hawach team to learn more.


Hawach filter paper

As a specialized grade BIO-4 micron filter manufacturer, Hawach has an extensive grade 4 micron filter paper production line, and each 20 micron filter paper BIO-4 has its own unique features, so that customers can choose the most optimized one according to their own filtration requirements.

Hawach uses the highest quality natural materials to ensure that each micron filter paper produced maintains consistent high quality, reproducibility and uniformity. Each filter paper undergoes rigorous testing before leaving the factory, including weight, thickness, gas flow rate and mechanical strength. In addition, individual parameters, such as particle retention, capillary action rate, filtration characteristics and apparent characteristics, can also be determined as needed.

Filter Paper Features

  1. Pore Size:
    • Filter papers are available in a range of pore sizes to accommodate different filtration needs. The pore size determines the size of particles that can be retained during the filtration process.
  2. Material Composition:
    • Filter papers are primarily made from cellulose fibers, but variations may include qualitative and quantitative grades, as well as those reinforced with other materials for enhanced strength and chemical resistance.
  3. Basis Weight:
    • The basis weight of filter paper is the weight per unit area (usually expressed in grams per square meter, g/m²). It indicates the thickness and density of the paper.
  4. Retention Efficiency:
    • Filter papers are rated for their ability to retain particles of a specific size. The retention efficiency is crucial in selecting the appropriate filter paper for a given filtration task.
  5. Flow Rate:
    • Flow rate refers to the speed at which liquid passes through the filter paper. It is influenced by factors such as pore size, thickness, and composition.
  6. Diameter and Shape:
    • Filter papers come in various diameters and shapes to fit different filtration apparatus. Common shapes include circular and folded filters.
  7. Qualitative vs. Quantitative Grades:
    • Filter papers are classified into qualitative and quantitative grades. Qualitative grades are used for general-purpose filtration, while quantitative grades are designed for precise analytical work where accurate measurements are essential.
  8. Chemical Compatibility:
    • Some filter papers are chemically treated to enhance their resistance to acids, bases, or other chemicals. The chemical compatibility of the filter paper should be considered based on the nature of the substances being filtered.
  9. Ash Content:
    • Ash content is the residue left when the filter paper is incinerated. Low ash content is desirable in applications where minimal interference from the filter paper is crucial.
  10. Particle Retention and Loading Capacity:
    • Filter papers vary in their particle retention capacity and loading capacity. The loading capacity refers to the amount of particulate matter the filter paper can hold before replacement is needed.

Qualitative filter paper

Standard grade qualitative filter paper

Hawach qualitative filter paper is used to identify the nature of substances in qualitative analysis techniques. Compared with the flat 20 micron filter paper of the same model, the folded qualitative filter paper accelerates the flow rate and increases the load.

Wet strength qualitative filter paper

This type of filter paper is very tough and has a high wet strength. In ordinary qualitative applications, no obvious impurities will be introduced. Note that it cannot be used for Kjeldahl determination.


Quantitative filter paper

Quantitative filter paper is an ordinary qualitative micron filter paper that is acidified to remove inorganic salts contained in the paper. After burning, the amount of residue is less than that of ordinary filter paper. In quantitative analysis, the weight of filter paper residue can be ignored.

Ashless quantitative filter paper

The ash content is extremely small, for example the grade 40 ~ 44 <0.007% very pure filter paper, which is the ideal paper for most of the main analysis filtration process.

Ash-free hardening quantitative filter paper

This series of filter paper has high strength and extremely low ash content (<0.006%). It is known as the cleanest analytical filter paper in the world. The tough surface makes this type of filter paper suitable for various strict filtration steps, and each level takes into account the filtration speed and particle retention.

Low gray hardening quantitative filter paper

The ash content is between ashless filter paper and qualitative filter paper (<0.015%). After strong acid treatment, trace metals are removed, resulting in high wet strength and chemical resistance. These filter papers are particularly suitable for Buchner funnels. The smooth surface makes it easy to recover the sediment.