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Features
*Quantitative Filter Papers
Ashless Grades (Ash 0.007%)
Grade 40: 8µm
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 spectro- photometry. Used also as a high purity filter in the
collection of trace elements and radionuclides from the atmosphere.
Grade 41: 20-25µm
The fastest ashless filter paper, recommended for
analytical procedures involving coarse particles or gelatinous
precipitates (e.g., iron or aluminium hydroxides). Also used in
quantitative air pollution analysis as a paper tape for impregnation when
determining gaseous compounds at high flow rates.
Grade 42: 2.5µm
A world standard for critical gravimetric analysis with
the finest particle retention of all Whatman cellulose filter papers.
Typical analytical precipitates include barium sulphate, metastannic acid
and finely precipitated calcium carbonate.
Grade 43: 16µm
Intermediate in retention between No. 40 and No. 41, and
twice as fast as No. 40. Typical applications include foodstuffs analysis;
soil analysis; particle collection in air pollution monitoring for
subsequent analysis by XRF techniques; and inorganic analysis in the
construction, mining and steel industries.
Grade 44: 3µm
Thin version of No. 42 retaining very fine particles but
with lower ash weight per sample and almost twice as fast
as No. 42. |