Whatman Grade 40 Ashless Filter Paper is designed for gravimetric analysis and the preparation of samples for instrumental analysis. The classic general-purpose ashless filter paper with medium speed and retention. Primary filter for separating solid matter from aqueous extracts in general soil analysis and quantitative determination of sediments in milk. It is used as a pure analytical grade clean-up filter for solutions prior to AA spectrophotometry; high purity filter in collecting trace elements and radionuclides from the atmosphere.

• High-purity filters contain 0.007% maximum ash content
• Medium nominal particle retention rating of 8 µm
• Medium filtration speed (Herzberg 340 s)
• Particularly useful for gravimetric analysis

Applications for high-purity Grade 40 filters

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. Whatman Grade 40 ashless paper is suited to:

• Soil analysis, when separating solid matter from aqueous extracts
• Quantitative determination of milk sediment
• Use as a clean-up filter for solutions prior to atomic absorption (AA) spectrometry
• Analysis of constituent components in cements, clays, iron, and steel products
• Collection of trace elements and radionuclides from the atmosphere

Specification:

¹Particle retention rating at 98% efficiency.

²For 9 cm diameter.

³Ash is determined by ignition of the cellulose filter at 900°C in air.