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MELIBE LEONINA
Filter Paper
Qualitative and quantitative filter papers for gravity and vacuum filtration. Available in standard grades, diameters from 55mm to 240mm, and ash content specifications for gravimetric analysis.
10+
Grades Available
55–240mm
Diameters
1–25µm
Retention Range
📝
Qualitative vs. Quantitative Filter Paper
Qualitative filter papers are used for routine filtration where the filtrate is the sample of interest. Quantitative (ashless) filter papers are used in gravimetric analysis where the paper is ashed and the residue weighed. Quantitative grades have ash content below 0.01%, ensuring negligible interference with mass measurements.
💡Selecting the Right Grade
Filter paper grades are classified by particle retention and flow rate. Fine grades (1–2 µm retention) offer high clarity but slow flow. Medium grades (5–8 µm) balance speed and clarity for most routine work. Coarse grades (15–25 µm) provide fast flow for gelatinous or coarse precipitates. Start with a medium grade and adjust based on your results.
FREQUENTLY ASKED
Filter Paper FAQ
Grade 1 (11 µm retention) is the most widely used qualitative filter paper, suitable for general-purpose filtration. Grade 2 (8 µm) provides slightly finer retention and is commonly used in soil analysis, seed testing, and food testing where higher particle removal is needed.
Use ashless (quantitative) filter paper whenever you plan to ignite the filter and weigh the residue, such as in gravimetric determination of calcium, barium, iron, or silica. The ash content is typically <0.01%, ensuring it does not contribute measurable mass to your results.
Match the paper diameter to your funnel. Common sizes: 90mm for 56mm funnels, 110mm for 65mm funnels, 125mm for 75mm funnels, and 150mm for 90mm funnels. The paper should sit flat against the funnel wall without extending above the rim.
Filter paper is generally not recommended for HPLC sample prep because the particle retention (1–25 µm) is far too coarse for analytical columns. Use 0.2–0.45 µm syringe filters or membrane filters instead.
Fold the circle in half, then in half again to form a quadrant. Open one side to create a cone with three layers on one side and one on the other. Seat the cone in a wetted funnel. For faster flow, use fluted (pleated) folding, which increases the exposed surface area.
Stocking a teaching lab or scaling up filtration?
We offer case-quantity pricing on all standard filter paper grades and diameters.