GRADE 4: 22 μm
Grade 4 filter paper is a standard grade filter paper used when high flow rates in air pollution monitoring are required and the collection of fine particles is not critical. Grade 4 filter paper is extremely fast filter paper with excellent retention of coarse particles and gelatinous precipitates such as ferric hydroxide and aluminum hydroxide.Very useful as a rapid filter for routine clean-up of biological fluids or organic extracts during analysis. These cellulose filters are used in qualitative analytical techniques to determine and identify materials.