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What is Grade 352?

Grade 352 high purity filters from Johnson Test Papers are general-purpose papers for quantitative analysis. This grade has medium flow rate and good particle retention and is the most commonly used acid-washed filter. High-purity filters support accurate analysis in applications sensitive to very low levels of background contamination and in gravimetric analysis where ash content might affect weight measurements of combusted samples.

Johnson Test Papers offers a range of ashless filter paper for your gravimetric analysis needs. See our other ashless grades to find the right filter for your sample, or use our hardened ashless grades if your analysis involves strong acid/alkali suspensions.

Grade 352 covers a wide range of general ashless analytical filtration applications.
  • It is used for gravimetric analysis of various components (e.g. cements, copper, clay, bismuth, silicon, iron) found in heavy industries such as construction, mining or steel.
  • It is also used for filtering sludges, determination of oils in waters and determination of sediments in milk.
  • Grade 352 is also used as a high purity filter containing 0.007% maximum ash content for speedy filtering of trace elements such as silver chromate, lead sulfate, coarser precipitates of calcium oxolate, zinc and ammonium hydroxide.
  • Grade 352 is also found in general soil analysis for separating solid from aqueous extracts.
  • Use as a clean-up filter for solutions prior to atomic absorption (AA) spectrometry Being a very pure filter, it can be used to capture radionuclides and traces of elements from the atmosphere.

Whatman Cross Reference = No.40
Speed class Medium Filtering
Thickness (mm) 0.16
Pore size (μM) 5-8
Weight (g/m²) 84
Filtration Speed (sec*) 50
Burst Strength (Kg/cm²) > 0.20
*According to DIN 53137
Available Sizes
Diameter (mm) Product Code
55 352055
70 352070
90 352090
110 352110
125 352125
150 352150
185 352185
240 352240
300 352300
320 342320