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    What is Grade 372?

    Johnson Test Papers’ Grade 372 is a high-purity, acid-treated cellulose laboratory filter paper. Mechanically strong, this grade has medium flow rate and quick particle retention and is most commonly used for quantitative or as a gravimetric filter during analysis requiring high chemical resistance to strong acid and alkali metal samples and in the collection of hydroxides. The acid-treated surface prevents tearing during filtration and allows the user to scrape precipitates from the paper.

    • Acid-treated for high wet-strength
    • Extremely low ash content (0.06% ash maximum).
    • Nominal pore size of 5 - 8 μm.
    • Medium flow rate (50 seconds according to DIN 53137).
    • High chemical resistance to strong acid and alkali suspensions.

    Johnson Test Papers offers hardened ashless filter paper for a variety of precipitate sizes. Along with general filtration Grade 372, the range includes Grade 371 for retention of fine precipitates and Grade 373 for fast filtration. All three grades are designed for use in gravimetric analysis.

    Grade 372 is often used for
    • Filtering trace elements.
    • Collecting hydroxides after precipitation by strong alkalis.
    • In the analysis of metals in acid and alkali solutions such as calcium oxalate and magnesium ammonium phosphate.
    • It can also be used for thick particles of barium sulfate and other phosphates.

    Whatman Cross Reference = No.52
    Speed class Medium
    Thickness (mm) 0.15
    Pore size (μM) 5-8
    Weight (g/m²) 84
    Filtration Speed (sec*) 50
    Burst Strength (Kg/cm²) >0.3
    *According to DIN 53137
    Diameter (mm) Product Code
    55 372055
    70 372070
    90 372090
    110 372110
    125 372125
    150 372150
    185 372185
    240 372240
    300 372300
    320 372300