Quantitative Filter Papers
What are Quantitative Filter Papers?
Quantitative Filter Papers, commonly known as ashless filter papers, are manufactured for applications where the residue on the paper is collected for subsequent weighing. Unlike qualitative papers, these filters undergo a washing process to remove impurities. This manufacturing method ensures that the paper leaves negligible ash residue after ignition, typically less than 0.01%, which is critical for precise gravimetric analysis. Borosil Scientific supplies these papers to support rigorous analytical testing where high purity is mandatory.
Key Features of Quantitative Filter Papers
Laboratory professionals select filtration media based on specific chemical and physical properties. The primary characteristics of these papers include:
- Ashless Composition: The papers are designed to burn off completely, leaving minimal residue that could affect weight measurements.
- High Purity: They are manufactured to minimise contamination of the filtrate or precipitate.
- Defined Retention Rates: Each grade is engineered to retain particles of specific sizes while allowing the solvent to pass through at controlled speeds.
These properties collectively ensure the reliability and accuracy of gravimetric analyses.
Grades and Types Available
The selection of the correct quantitative filter papers depends on the nature of the precipitate and the required filtration speed. Borosil Scientific offers distinct grades tailored to specific laboratory requirements.
| Grade | Filtration Speed | Retention / Porosity | Filtration Herzberg | Weight [g/m²] |
Characteristics |
| B58940 | Medium | 2–4 micron | 450 s | 84 | For fine crystalline precipitates and routine gravimetric analysis. |
| B58941 | Fast | 12-25 micron | 50s | 79 | For coarse and gelatinous precipitates with rapid flow. |
| B58942 | Slow | <2 micron | >750s | 84 | For very fine crystalline precipitates requiring slow filtration. |
| B58943 | Medium Fast | 4-12 micron | 140s | 85 | For coarse precipitates with balanced speed and retention. |
| B58944 | Slow (Thin) | 2 micron | 140s | 74 | For fine crystalline precipitates with slower flow. |
Applications of Quantitative Filter Papers
These filtration products are utilised in industries requiring exact measurements and minimal contamination. Common applications include:
- Gravimetric Analysis: Separation of solids from liquids, where the weight of the solid is the primary data point.
- Environmental Monitoring: Filtration of water or soil samples to determine suspended solids or specific contaminants.
- Food and Beverage Testing: Analysis of food content, such as fibre determination or sugar analysis.
- Pharmaceutical Analysis: Quality control testing to ensure products meet purity standards.
- Chemical Analysis: Preparation of samples for instrumental analysis where particulate removal is necessary.
The appropriate grade of filter paper must be selected to match the specific requirements of these applications.
Why Choose Borosil Scientific?
Borosil Scientific filter papers are made in collaboration with Hahnemühle (since 1883). Containing up to 98% alpha cellulose, they offer high stability and durability. Manufactured without recycled materials for consistent performance and featuring very low ash content (as low as 0.004%) for accurate analysis. Made in Germany to stringent European quality standards for premium performance.
Product Specifications & Options
The physical specifications of Borosil Scientific quantitative filter papers are controlled to meet the demands of analytical workflows.
| Specification | Details |
| Ash Content | Average 0.004% |
| Thickness Range | 0.15mm to 0.19mm(varies by grade) |
| Weight Range [g/m²] | 74 to 85 |
| Format | Circles and sheets (Standard laboratory funnel sizes) |
Hardened ashless filter paper quantitative papers are typically used for gravity filtration. For applications involving vacuum or pressure, please verify the wet strength specifications in the product datasheet to prevent rupture.
Hardened Ashless Filter Papers
Designed for quantitative and gravimetric analysis under high pressure or aggressive chemical conditions.
- Avg. ash content: 0.003%
- Very high wet strength for easy precipitate removal
- Hardened with nitrogen-containing resin without contaminating filtrate
- Resistant to acids (up to 40% at 50°C) and alkalis (up to 10% at 20°C)
Made from super-refined cotton linters with >98% alpha cellulose for superior stability and durability
The specific pore size and retention capability vary by grade (B58940 through B58944). Users should consult the technical brochure to match the grade with the particle size of the precipitate.
Yes, these papers are supplied in various standard diameters to fit different funnel sizes. Please check the Borosil Scientific product listing for exact dimensions.
Institutions with large-volume requirements should contact Borosil Scientific directly to discuss bulk ordering options or specific size requirements.
Qualitative papers are used for general filtration, where the recovery of the precipitate is not required for weighing. Quantitative Filter Papers are treated to be ashless, making them suitable for gravimetric analysis where the precipitate must be weighed after ignition.