Whatman 1442-150 Filter Circles, 150mm Dia, Ashless Grade 42, 100/pk (PN:1442-150)

Whatman Grade 42 ashless filter paper is designed for high-precision laboratory filtration, especially in gravimetric analysis and sample preparation for instrumental analysis. Its high purity ensures that residue left after burning (ashing) is extremely low, which is essential when accurate weight measurements are required.

Grade 42 filter paper provides very fine particle retention of about 2.5 µm, making it one of the finest retention grades among Whatman cellulose filter papers. This allows it to capture extremely small precipitates and suspended solids during analytical filtration.

Ashless filter papers are manufactured with very low ash content (around 0.007%), which means they leave almost no residue after combustion. This property is critical in gravimetric testing because any remaining ash could interfere with precise mass measurements of the sample residue.

Grade 42 filter paper is often used to filter fine precipitates such as calcium carbonate, barium sulfate, and other analytical compounds. These applications are common in industries like cement testing, coatings, pigments, and environmental analysis.

The 150 mm diameter format is typically used in large filtration setups such as Buchner funnels, vacuum filtration assemblies, and environmental sample filtration systems. The larger size allows laboratories to process higher sample volumes efficiently.