What is the difference between quantitative filter paper and qualitative filter paper? 

Qualitative filter paper

Qualitative filter papers are used when substance separation is necessary to identify material content. Qualitative filter paper offers a range of retention and flow options for a wide variety of laboratory processes. Nominal retention ranges from 2 to 20 micrometers, and thicknesses between 150 and 320 micrometers are available from specialty paper manufacturers. Filtration rate of qualitative filter paper is based on retention and thickness specifications, and these factors are related to the speed of filtration processes. Qualitative filter papers are used for qualitative analytical techniques to separate and identify substances.

Quantitative filter paper

Quantitative filter papers, also known as hardened filter papers, are used for quantitative and gravimetric analyses using pressure or vacuum filtration methods, especially when remaining precipitate is to be analyzed – and when minimal ash content is required.

Specialty paper manufacturers use acid wash methods to reduce ash content while achieving a high level of purity. The amount of ash produced by quantitative filter papers after furnace disposal is 0.0009% or less. Ash weight is insignificant and does not impact analytical results.

In addition, quantitative filter papers have superior wet strength in order to endure both pressure filtration and vacuum filtration. Qualitative filter paper by contrast has comparatively low wet strength. However, moisture-strengthened qualitative filter paper is also available for pressure and vacuum filtration.