Whatman Grade 540 is a high-purity, acid-treated cellulose lab filter paper. Mechanically strong Grade 540 is well suited for quantitative or gravimetric analysis of strongly acidic or alkaline samples.
• Acid-treated for high wet-strength
• Extremely low ash content (0.006% ash maximum)
• Nominal particle retention of 8 µm
• Medium flow rate (Herzberg filtration speed 200 s)
• High chemical resistance to strong acid and alkali suspensions
We offer hardened ashless filter paper for a variety of precipitate sizes. Along with general filtration Grade 540, the range includes Grade 542 for retention of fine precipitates and Grade 541 for fast filtration. All three grades are designed for use in gravimetric analysis.
Gravimetric analysis of acid and alkali suspensions
Whatman hardened, ashless Grade 540 lab filter paper is frequently used as a gravimetric filter during analysis of metals in acidic or alkaline solutions and in the collection of hydroxides. The acid-treated surface prevents tearing during filtration and allows the user to scrape precipitates from the paper.