whatman grade 50/52/54/540/541/542硬化无灰定量滤纸quantitative filter papers - hardened low ash grades (ash 0.015%)
the maximum ash content of these grades is intermediate between ashless and qualitative grades. they are particularly suitable for buchner filtrations where it is desirable to recover the precipitate from the filter surface after filtration. other characteristics include high wet strength and chemical resistance which are similar to the acid hardened ashless filter papers.
quantitative filter papers - hardened ashless grades (ash 0.006%)
these are the supreme quantitative filter papers featuring high wet strength and chemical resistance. these papers are acid hardened, which reduces ash to an extremely low level. their tough surfaces make them suitable for a wide range of critical analytical filtration operations. each grade offers a convenient combination of filtration speed and particle retention.