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Filter Paper Grades: A Guide to Qualitative Filter Paper

Our Qualitative Filter Papers come in different grades and each serves a very different purpose for a variety of uses. Qualitative filter papers are considered general purpose filter papers. Qualitative filter papers have a higher ash content which makes them better suited for more general purposes. They can be used for many different applications, both in and out of the laboratory. 

But most important to choosing the correct qualitative filter paper is making sure you have the correct grade quality for the job. Different grades of filter paper serve different purposes. This guide is to help you make an informed decision and get the correct tools to do the job. 

What is Qualitative Filter Paper?

Qualitative filter paper is used in qualitative laboratory analysis and corresponding filtration separation. This means that it is best used for the analysis of what the components of a substance are. This filter paper is best used for when you are determining the different components of a substance. 

Qualitative filter paper can serve a variety of purposes and knowing what grade best serves your purpose is important and we are here to help you make that decision. These grades vary in porosity, flow rate, and particle retention. Each one serves a specific purpose. 

Here at Tisch Scientific the different grades of qualitative filter paper we offer are all glass fiber filter paper. 

Glass Fiber Filter Paper

Glass Fiber Filter Papers are made of 100% borosilicate glass. Borosilicate glass is a type of glass that contains boron trioxide. This makes the glass extremely durable and unlikely to crack under extreme pressure. These filter papers are used for hard to filter substances or for prefilateration. These papers can come in binder glass microfiber or binder glass free microfiber. 

There are several attributes that separate the different grades of qualitative filter paper. 

  • Porosity 

Porosity refers to the porous nature of the filter. The density and type of pores in the filter affect the bubble point and the rate at which liquid can be absorbed and flow through the filter. 

  • Flow Rate

The flow rate is the speed at which a substance passes through a filter. The flow rate of a membrane filter is an important factor to consider when choosing a filter for your application 

  • Particle Retention 

Particle retention is the rate at which a filter will retain particles in a filtration process. Particle retention is crucial when trying to separate contaminants and other substances during lab analysis. 

To break down these grades in simple terms we’ve built a chart here. 

GradePorosityFlow RateParticle Retention 
AFine Fast 1.6 m
BFine Medium to Fast1.0 m 
CFine Fast 1.2 m
DCourse Fast 2.7 m 
EFine Fast 1.3 m 
FFine Medium 0.7 m 

But we can also break down these grades a bit more. 

Grade A

Grade A filter paper is the most widely used paper when requiring medium retention. This filter paper is efficient in seed analysis and soil testing, collecting dust in the atmosphere, Separating food particles from liquids, and gas detection. Grade A filter paper is also the most commonly used for clarifying liquids. 

Grade B 

Grade B filter paper serves the purpose of being more retentive than Grade A filter paper and thus can be more effective in more particular applications. This filter paper can be a great option when it comes to plant growth trials. Grade B filter paper is a great choice when it comes to soil and plant monitoring.

Grade C

Grade C filter paper has an increased strength while wet because it is double the thickness of Grade A filter paper. It can hold more liquid without clogging and is a great choice for transporting a sample after collection. 

Grade D

Grade D filter paper is a great choice for retention of coarse particles and gelatinous materials. This makes this paper efficient in air pollution monitoring when collecting tiny particles is not a concern. Grade D filter paper can also be used in biological and organic extract clean up. 

Grade E  

Grade E filter paper boasts the highest level in particle retention for qualitative filter papers. This grade of filter paper is efficient at clearing cloudy substances for water and soil analysis. 

Grade F 

Grade F filter paper has a similar retention rate to Grade E but boasts a flow rate twice as fast. It is a great choice for boiler water analysis because of its absorbency and strength. This makes Grade F filter paper the correct choice for air and soil containment monitoring and plant growth trials. 

In Conclusion 

Whatever your application or laboratory process we have a qualitative filter paper to meet your needs. With a wide variety of different grades all at an affordable price we are here to help you and your team get the right tools for the job. If you are still unsure what would be the best choice for your job we are happy to connect you with our friendly customer support team to determine what would best fit your needs. 

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