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    What is Grade 50A?

    Johnson Test Papers’ Grade 50A glass microfibre filters offers fine particle retention with high filtration speed and good loading capacity. 50A filters are suitable for water quality parameter measurement and air filtration applications.

    • Suitable for a wide range of liquid and air filtration applications
    • Nominal pore size of 1.6 µm
    Johnson Test Papers offers a variety of binder-free glass microfiber filters for different sample types and analysis needs. For higher wet strength, increased loading capacity, or different particle retention, see Johnson Test Papers’ other binder-free filter options.
    Johnson Test Papers glass microfibre filters without binder

    Filters that combine high loading capacity with fine particle retention are highly efficient for applications such as general laboratory filtration, clarification of buffer and reagent solutions, wastewater and water in general. Grade 50A meets these requirement as well as being useful for water quality parameter measurements involving large sample volumes. Grade 50A filters can function as wastewater filters or serve as filters in the following applications:

    • Water pollution monitoring of effluents
    • Foodstuff analysis
    • Radioimmunoassay of weak β emitters
    • Gravimetric determination of airborne particulates
    • Atmospheric and water pollution monitoring such as intake controls, ozone-level, and water effluents.
    • Filtration of water and protein
    • Testing of algae, bacteria cultures
    • Filtering solvents in a high-resolution laboratory.
    • Scintillation counting on the filter
    • Cell harvesting
    • Hydrocarbon analysis where cellulose fibers are an inconvenience

    Grade 50A corresponds to many international standards for air and water pollution monitoring

    Whatman Cross Reference = No.GFA
    Speed class Fast, high loading
    Thickness (mm) 0.26
    Pore size (μM) 1.6
    Weight (g/m²) 52
    Filtration Speed (sec*) 60
    Burst Strength (Kg/cm²) 20
    *According to DIN 53137
    Diameter (mm) Product Code
    mm: 21 Product code: 50A021
    mm: 24 Product code: 50A024
    mm: 25 Product code: 50A025
    mm: 47 Product code: 50A047
    mm: 55 Product code: 50A055
    mm: 90 Product code: 50A090
    mm: 110 Product code: 50A110
    mm: 125 Product code: 50A125