Grade 4 Qualitative Filter Paper, Standard Grade

A standard grade filter used when high flow rates in air pollution monitoring are required and the collection of fine particles is not critical.

These cellulose filters are used in qualitative analytical techniques to determine and identify materials. Prepleated qualitative filters are also available, which give improved flow rate and increased loading capacity compared to equivalent flat filters.

Grade 4: 25 µm

Extremely fast filtering with excellent retention of coarse particles and gelatinous precipitates such as ferric hydroxide and aluminum hydroxide. Very useful as a rapid filter for routine clean-up of biological fluids or organic extracts during analysis. Used when high flow rates in air pollution monitoring are required and the collection of fine particles is not critical.

Specifications:

• Grade: Grade 4
• Grade Type: Standard
• Typical Particle Retention in Liquid: 25 µm
• Typical Water Flow Rate (ml/min) for 9cm diameter: 247
• Nominal Thickness: 210 µm
• Nominal Basis Weight: 92 g/m²
• Nominal Air Flow Rate: 4s/100ml/in²
• Nominal Ash Content: 0.06%
• Material: Cellulose
• Typical Trace Element Levels: Aluminium 3.6 µg/g, Antimony <0.5 µg/g, Arsenic <0.5 µg/g, Barium <0.5 µg/g, Boron <1 µg/g, Calcium 27.5 µg/g, Chromium 1 µg/g, Copper 0.9 µg/g, Iron 13.7 µg/g, Lead <0.5 µg/g, Magnesium 21 µg/g, Manganese <0.5 µg/g, Mercury <0.5 µg/g, Potassium 6.2 µg/g, Silicon 8.8 µg/g, Sodium 32.3 µg/g, Zinc 58.3 µg/g

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