Our high-purity Whatman ashless Grade 42 quantitative filter papers are suitable for a wide range of critical analytical filtration procedures for quantitative analysis. Grade 42 filter papers have the finest retention of all Whatman ashless filter paper grades. Grade 42 is designed for gravimetric analysis and sample preparation for instrumental analysis. Ashless: 0.007% ash maximum Fine (2.5 μm) nominal particle retention rating, eliminates large particles that might otherwise interfere with sensitive instrumentation Herzberg filtration speed of 1870 s Commonly used as a calcium carbonate filter Particularly suitable for gravimetric analysis Whatman Grade 42 quantitative papers from Cytiva business are designed for retention of extremely small particles. A common example is use of Grade 42 as a calcium carbonate filter for analysis in the cement industry. Other typical precipitates for gravimetric analysis include barium sulfate and metastannic acid for use in glazes, coatings, and pigments. The high purity of Cytiva's Grade 42 filters also makes them suitable for processes that require ashing. Ashless filter papers for gravimetric and instrumental analysis Cytiva offers a range of Whatman ashless filter papers for your gravimetric analysis needs. See our other Whatman ashless grades to find the right filter paper for your sample, or use our hardened Whatman ashless filter paper grades if your analysis involves strong acid or alkali suspensions. What are Whatman ashless quantitative filter papers? Whatman ashless quantitative filter papers are high-purity filters that 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. Cytiva's high-purity Whatman ashless filter papers are suited for: Environmental analysis: soil filtration analysis, when separating solid matter from aqueous extracts Retention of small particles Collection of trace elements and radionuclides from the atmosphere Are you looking for a filter paper, membrane filter, or syringe filter? Let Cytiva help you find the optimal filter for your needs to ensure reliable analysis with our filter selector and size chart.