Whatman Grade 40 high-purity filters are general-purpose papers for quantitative analysis. Grade 40 filters are suitable for a variety of analytical filtration applications.

• 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

Whatman quantitative filters are designed for gravimetric analysis and the preparation of samples for instrumental analysis. They are available in three formats designed to meet your specific needs.

Ashless: 0.007% ash maximum for Grades 40 to 44 and a maximum of 0.01% for the 589 Grades – very pure filters suitable for a wide range of critical analytical filtration procedures.

Grade 40: 8 μm (Medium Flow Filter Paper)

The classic general purpose ashless filter paper with medium speed and retention. Typical applications include gravimetric analysis for numerous components in cements, clays, iron, and steel products; as a primary filter for separating solid matter from aqueous extracts in general soil analysis, quantitative determination of sediments in milk and as a pure analytical grade clean-up filter for solutions prior to AA spectrometry.

Also used as a high-purity filter in the collection of trace elements and radionuclides from the atmosphere.

Materials and Methods

High molybdenum analysis

The performance of quantitative filter paper is important in high molybdenum (Hi Mo) testing. The major critical to quality (CTQ) factors in performance testing are filtration speed, clarity of filtrate, and molybdenum (Mo) content. Analyses were performed on ten samples using Whatman Grade 40 paper and the following procedure.

Zinc analysis

The zinc test is one of most important metal tests in mining applications. The performance of quantitative filter paper is critical during sample preparation steps in zinc analysis. The major critical to quality (CTQ) factors in performance testing are filtration speed, clarity, and zinc (Zn) content. Analyses were performed on ten samples using Whatman Grade 41 quantitative filter paper and the following procedure.

The results for ten samples of Whatman Grade 41 quantitative ashless filter paper used in zinc analysis are provided in Table 3. Consistent filtration speed and performance were achieved. The customer is satisfied with the performance of Grade 41 Whatman filter paper in zinc analysis.

Conclusion

This work demonstrates that Grades 40 and 41 of Whatman quantitative filter paper show good separation performance, speed, and repeatability in high molybdenum, lead, and zinc analyses. All of the customer requirements were met for all three tests. Therefore, these papers have the potential to improve the quality control process in mining industries.