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    371

    What is Grade 371?

    Johnson Test Papers’ Grade 371 filters are acid hardened to allow high retention of fine precipitates in applications such as metal determinations and hydroxide collection.

    • High wet-strength
    • Acid-hardened for resistance to strong acid and alkali solutions
    • Nominal pore size of 2-3 ‎μm
    • Filtration speed of 180 seconds according to DIN 53137
    • Extremely low ash content (0.06% ash maximum)

    Along with Grade 371 cellulose filter paper, the Johnson Test Papers range of hardened ashless quantitative papers includes fast Grade 373 and general-purpose Grade 372 filters. All three grades are designed for use in quantitative analysis with strong acid/alkali solutions.

    Grade 371 is a very dense and thick filter paper with a slow filtration speed.

    This is an extremely fine retention filter for critical gravimetric analysis in chemically harsh conditions and metal determination of very fine precipitates or difficult samples such as metals and hydroxides i.e.

    • barium and lead sulfates and dioxide
    • stannic, zinc and nickel sulfide
    • calcium oxalate
    • calcium fluoride

    Whatman Cross Reference = No.50
    Speed class Slow
    Thickness (mm) 0.14
    Pore size (μM) 2-3
    Weight (g/m²) 84
    Filtration Speed (sec*) 180
    Burst Strength (Kg/cm²) >0.3
    *According to DIN 53137
    Diameter (mm) Product Code
    mm: 55 Product code: 371055
    mm: 70 Product code: 371070
    mm: 90 Product code: 371090
    mm: 110 Product code: 371110
    mm: 125 Product code: 371125
    mm: 150 Product code: 371150
    mm: 185 Product code: 371185
    mm: 240 Product code: 341240
    mm: 300 Product code: 371300
    mm: 320 Product code: 371300