Whatman 1440-150 Filter Circles, 150mm Dia, Ashless Grade 40, 100/pk (PN:1440-150)

Whatman Grade 40 ashless filter papers are widely used in quantitative laboratory analysis, especially in procedures such as gravimetric testing, soil analysis, and preparation of samples for instrumental techniques. Their high purity makes them suitable for analytical applications where residue or contamination must be minimized.

Grade 40 filter paper provides a nominal particle retention of approximately 8 µm, which allows efficient separation of medium-sized precipitates while maintaining good filtration speed. This balance makes it suitable for routine analytical filtration tasks in many laboratories.

Ashless filter paper contains extremely low mineral residue—typically no more than about 0.007% ash content—so it can be completely burned without leaving significant residue. This is essential in gravimetric analysis where the weight of combustion residue could otherwise affect measurement accuracy.

Grade 40 filter paper is commonly used in environmental testing, mining analysis, food testing, and materials laboratories. Typical applications include determining sediment in milk, analyzing soil extracts, and measuring components in materials such as cement, clay, iron, and steel.

The 150 mm diameter format is designed for use with large laboratory filtration funnels and gravity filtration setups. The larger surface area helps handle larger sample volumes and improves filtration efficiency when processing bulk laboratory samples.