Macherey-Nagel quantitative filter paper circles, grade MN 640 w, ash-free, fast-filtering (Ø 55–320 mm), 90 mm
€19.90
% Manufacturer's RRP: €24.00 17% below manufacturer's RRP
- Ash-free quantitative filter paper circles, grade MN 640 w, from Macherey-Nagel for precise gravimetric analysis
- Acid-washed paper with an extremely low ash content of less than 0.01 %
- A short filtration time of approx. 9 seconds accelerates the separation of coarse and bulky precipitates
- Binder-free non-woven fabric made from pure cellulose reliably protects the filtrate from extractable residues
- A scalable range of sizes from 55 mm to 320 mm in diameter accommodates any funnel or Büchner funnel geometry
Product information "Macherey-Nagel quantitative filter paper circles, grade MN 640 w, ash-free, fast-filtering (Ø 55–320 mm), 90 mm"
The Macherey-Nagel quantitative filter paper circles of the premium MN 640 w grade represent a system solution optimised in terms of materials science and highly efficient in terms of fluid mechanics, designed for precise gravimetric analysis, the quantitative separation of solids and demanding sample preparation in day-to-day laboratory work. Available in a range of diameters from 55 mm for small-scale analytical applications up to large-area 320 mm filters for high-volume separation processes, this filter series caters for every scale of modern laboratory processes. For quantitative determinations in environmental analysis, metals and building materials chemistry, as well as in pharmaceutical purity testing, the uncompromising purity of the filter medium is the primary criterion for working in a way that is gentle on materials, contamination-free and process-reliable.
Very low ash content for gravimetric analyses
The technological basis of the MN 640 w grade is founded on ultra-pure raw materials such as refined alpha-cellulose and high-quality linters. In a specialised, materials science-based refinement process, the paper is washed with acids to achieve an extremely low ash content of less than 0.01 %. This very low ash content ensures that, during the subsequent incineration of the filter in a muffle furnace, hardly any mineral residues remain that could distort the measurement result on the analytical balance. For B2B testing laboratories, this filter medium thus provides a reliable metrological basis for reproducible and highly precise determinations of weight constancy.
Optimised pore structure for fast kinetics and coarse precipitates
From a fluid mechanics perspective, the smooth filter paper circle is characterised by a deep, wide-pore structure that has been specifically optimised for maximum filtration speed. With a standardised filtration speed of approximately 9 seconds according to the manufacturer’s specification, the MN 640 w grade allows for an extremely rapid liquid throughput. The paper is therefore well suited to the separation of coarse, voluminous and crystalline precipitates (such as iron hydroxide, aluminium hydroxide or coarse metal sulphates). The high porosity minimises flow resistance, thereby reducing undesirable blocking effects (filter clogging) in a way that is gentle on the material and process-reliable, even with sample flows heavily laden with particles.
High wet tear strength for demanding routine processes
Despite the absence of artificial binders or chemical additives, the homogeneous non-woven fabric possesses remarkable inherent mechanical stability. The optimised fibre interlacing gives the filter high wet tear strength, enabling it to withstand hydrodynamic pressure during funnel filtration or when a light vacuum is applied without any problems. For laboratory managers and quality management personnel in regulated environments, Macherey-Nagel’s MN 640 w filters provide a basis for recurring quantitative testing processes.
Technical details
Material science & filter structure
- Filter type: Quantitative filter paper / Ash-free filter paper circle
- Grade / Quality level: MN 640 w
- Material base: Alpha-cellulose and linters
- Finishing: Acid-washed (for maximum purity)
- Ash content: less than 0.01 % (low residue when incinerated)
- Surface structure: Smooth, homogeneous non-woven structure
- Filtration properties: Fast filtration (for coarse and crystalline particles)
- Filtration speed: approx. 9 seconds (standardised according to manufacturer’s specifications)
Physical properties & dimensions
- Grammage: approx. 85 grams per square metre (85 g/m²)
- Filter thickness: approx. 0.20 mm (millimetres)
- Available diameter range: 55 mm to 320 mm
- Diameter variants in the range: 55, 70, 90, 110, 125, 150, 185, 240, 320 mm
- Cut: Geometrically precise, fibre-free circular cut
Resilience & compliance
- Chemical resistance: Universally inert to mild acids, alkalis and organic solvents
- Wet tear strength: High (structurally stable under fluid load)
- Application: Gravimetric analyses
Scope of delivery
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1 x pack of Macherey-Nagel quantitative filter paper circles, grade MN 640 w, ash-free, fast (standard contents: 100 pieces per box) in the diameter selected by the customer (55 mm to 320 mm).
Individual requirements & accessories
To ensure the optimal integration of Macherey-Nagel quantitative filters into your daily analytical routine, we offer a comprehensive range of suitable laboratory peripherals. For conventional vacuum filtration, we offer chemically highly resistant porcelain Büchner funnels, matching borosilicate glass suction flasks and complete multi-filter units. For contamination-free and gentle handling of the ash-free filter paper circles, we recommend flat-tipped filter tweezers made from high-alloy stainless steel. For subsequent thermal treatment, our range includes high-purity porcelain crucibles, crucible tongs and desiccators for moisture-protected cooling. Please make use of our technical procurement service to tailor the design of your analytical workstations to your specific requirements.
| Diameter: | 90 mm |
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