Macherey-Nagel MN 85/90 round glass fibre filter with binder, 0.5 µm (Ø 25 mm – 320 mm)

Macherey-Nagel MN 85/90 round glass fibre filters, renowned for their premium quality, represent a system solution optimised in terms of materials science and offering high mechatronic stability for demanding clarification, particle separation and sample preparation in modern day-to-day laboratory work. Available in a wide, application-specific range of diameters – from 25 mm for compact in-line filtration systems up to large-area 320 mm for high-volume funnel and Nutsch set-ups – this series caters for all scales of analytical and process engineering applications. As the most widely used glass fibre filter for general laboratory applications, this filter media is employed wherever excellent flow rates must be combined with outstanding mechanical strength in order to separate particle-rich media in a way that is gentle on the material and ensures process reliability.

Outstanding mechanical stability thanks to organic binders

The unique technological feature of the MN 85/90 grade is based on the targeted combination of high-purity borosilicate glass microfibres with a specialised organic binder. Whilst binder-free glass fibre filters may be prone to fibre shedding under intense fluid-mechanical stress or strong mechanical shearing, the binder matrix permanently stabilises the fibre structure. This gives the smooth round filter remarkable tear resistance and inherent stability when wet. With a filter thickness of 0.6 mm and a defined basis weight of 90 grams per square metre (90 g/m²), the filter’s three-dimensional depth structure remains completely dimensionally stable even under high filtration pressure, which reliably prevents transient filter breakthrough.

Highly efficient separation and rapid filtration kinetics

From a metrological perspective, the MN 85/90 filter offers an extremely fine nominal retention capacity of 0.5 micrometres with a separation efficiency of at least 99.99 per cent. This fine pore structure makes the filter medium ideal for the reliable separation of the finest precipitates, microparticles and macromolecular aggregates. Despite this high retention capacity, the high porosity of the glass fibre fleece guarantees a remarkable hydrodynamic flow rate: with a standardised filtration time of 15 seconds, flow resistance is minimised, thereby significantly speeding up time-critical routine analyses and high-throughput filtration. Undesirable clogging effects (blocking) in heavily particle-laden sample flows, such as wastewater or sludge samples, are reduced in a way that is gentle on the material.

Thermal resistance and comprehensive quality management

The thermodynamic limit of the MN 85/90 filter is set at a maximum temperature of 200 degrees Celsius due to the organic binder component. Up to this threshold, the material remains absolutely structurally stable, chemically inert and colourfast (pure white). The filter’s smooth surface prevents irreversible adsorption of sample components and allows for residue-free handling. For laboratory managers and quality management officers in regulated environments, Macherey-Nagel’s range provides a reliable and audit-compliant validation basis for carrying out recurring test processes and certifications in accordance with GLP and GMP guidelines in a process-reliable manner.

Technical details

Material Science & Filter Structure

• Filter type: Glass fibre depth filter / round filter
• Grade / Quality level: MN 85/90
• Material basis: High-purity borosilicate glass microfibres
• Binder status: With organic binder (for maximum mechanical strength)
• Surface finish: Smooth, uniformly structured
• Colour: White
• Nominal retention capacity: 0.5 micrometres
• Separation efficiency: greater than or equal to 99.99 per cent

Physical & kinetic properties

• Basis weight: approx. 90 grams per square metre (90 g/m²)
• Filter thickness: approx. 0.6 mm (millimetres)
• Filtration rate: 15 seconds (standardised according to the manufacturer’s specifications)
• Air filtration rate: 15 seconds
• Thermal stability: Remains stable up to a maximum of 200 degrees Celsius (392 degrees Fahrenheit)

Dimensions, Logistics & Compliance

• Available diameter range: 25 mm to 320 mm
• Common diameter variants: 25, 37, 45, 55, 70, 90, 110, 125, 150, 185, 240, 270, 320 mm
• Hazard classification according to GHS: Not classified as a hazardous substance; completely safe to handle
• Quality management: Supports standardised, reproducible routine filtration procedures in accordance with GLP

Contents of delivery

• 1 x pack of Macherey-Nagel glass fibre round filters, grade MN 85/90, with binder (standard contents: 100 pieces per box) in the diameter selected by the customer (25 mm to 320 mm).

Customised requirements & accessories

To ensure the optimal integration of Macherey-Nagel glass fibre filters into your daily laboratory routine, we offer a comprehensive range of complementary peripherals. For classic vacuum or Büchner filtration, our portfolio includes robust porcelain Büchner funnels, suitable suction flasks made from thick-walled borosilicate glass, and complete multi-stage filtration units made from stainless steel. For contamination-free and gentle handling of the sensitive filter discs, we recommend the use of flat-tipped filter tweezers made from high-alloy, corrosion-resistant stainless steel. For subsequent drying processes until a constant weight is achieved at temperatures of up to 200 degrees Celsius, we also offer chemically inert Petri dishes and desiccators. Please make use of our technical procurement service to design your filtration workstations to suit your specific requirements.