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.

Grade 50: 2.7µm
Retention of finest crystalline precipitates. The thinnest of all Whatman filter papers. Slow flow rate. Hardened and highly glazed surface. This finish also keeps the paper free from loose surface fibres. Highly suitable for qualitative or quantitative filtrations requiring vacuum assistance on Büchner or 3-piece filter funnels. Very strong when wet. Will withstand wet handling and precipitate removal by scraping. In the electronics industry, the virtual absence of fibre shedding is utilised in carriers for integrated circuits.Grade 52: 7µm
The general purpose hardened filter paper with medium retention and flow rate. Very hard surface. Grade 54: 20-25µm
Very fast filtration for use with coarse and gelatinous precipitates. High wet strength makes this grade very suitable for vacuum assisted fast filtration of "difficult" coarse or gelatinous precipitates. Grade 540: 8µm
The general purpose hardened ashless filter paper with medium retention and flow rate. Extremely pure and strong with a hard surface. High chemical resistance to strong acid and alkali. Frequently used in the gravimetric analysis of metals in acid/alkali solutions and in collecting hydroxides after precipitation by strong alkalis. Grade 541: 20-25µm
Fast filtration of coarse particles and gelatinous precipitates in acid/alkali solutions during gravimetric analysis. Typical applications include fibre in animal foodstuffs, gelatine in milk and cream, chloride in cement, and chloride and phosphorous in coal and coke. Grade 542: 2.7µm
High retention of fine particles under demanding conditions. Slow flow rate. Very hard and strong with excellent chemical resistance. Often used in gravimetric metal determinations.

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.