Filter paper, qualitative

Medium fast, 4 - 7µm

• thicker and faster than 595
• for medium to fine precipitates
• Weight 85 g/m²
• Thickness 0.180 mm

Compatible with Hirsch or Büchner funnels, average thickness 115 µm. Acid-treated for high wet-strength and chemical resistance.

• Nominal particle retention of 2.7 µm
• Slow flow rates (Herzberg filtration speed 2685 s)
• High purity and low ash content (0.015 % ash maximum)

Medium to fast, 8 to 10µm

• thick filter paper
• for fast filtration of coarse precipitates
• Weight: 140g/m²

Fast, 12 to 25µm

• time saving, because folded filters have a larger surface area
• filter faster than comparable circular filters
• for coarse precipitates (e.g. hydroxide and sulphide)
• Weight: 80g/m²
• Thickness: 0.19mm

Medium fast filtration, suitable for many applications such as for sulphides, lead chromate and calcium oxalate.

CHROMAFIL^® syringe filters are used for filtration of suspended matter from liquid samples. HPLC-Certification available on the internet
Polypropylene housing
Better solvent stability compared to acrylate and polystyrene filters
Shells ultrasonically sealed, not glued
No extractable components from glues
Filtration in both directions possible, the liquid cannot bypass the membranes
Luer lock on side of entry
Safe connection on the "high pressure" side
Luer exit
Standard luer for 3mm and 25mm filters, minispike luer with low dead volume and small OD for 15mm filters
Deflector
The stream of liquid is broken and distributed, and does not directly hit the membrane: this prevents rupture of the membrane
Star-shaped distribution device
The liquid is evenly distributed to the whole membrane surface: this results in a better utilisation of the total area; the filter is not rapidly clogged up; high flow efficiency
Colour coded
Filters with 0.2µm pores have a yellow upper housing, for filters with 0.45µm pores this is colourless; the different membrane types are distinguished by different colours
Low dead volume
~80µl for 25mm, 35µl for 15mm, 5µl for 3mm.

Specifications
The membrane housing consists of polypropylene (PP). This material is very resistant towards most solvents and has a very low extractable substances content. Thus it can be used with almost all solvents, acids and bases (see table). The especially thick rim of the housing is ideal for use with laboratory robots (e.g. Benchmate™). Filter inlet and filter outlet can be fitted to the CHROMABOND^® columns for selective sample preparation with the aid of a special adaptor. All filters can be autoclaved at 121°C and 1.1bar for 30min.

Chromafil™Xtra:
Labelled for method validation and certification. Colour-free plain polypropylene housing. Imprint for direct identification of the membrane type, diameter and pore size.
A hydrophobic membrane. Ideal for filtration of non-polar liquids and gases. It is very resistant to various solvents as well as acids and bases. By flushing with alcohol, followed by water, the original hydrophobic membrane can be made more hydrophilic.

Circles. Qualitative. Slow flowrate. Retains fine precipitates, grained surface. Supplied in packs of circles as outlined below.

• Acid-treated for high wet-strength
• Extremely low ash content (0.006 % ash maximum)
• Nominal particle retention of 8 µm
• Medium flow rate (Herzberg filtration speed 200 s)
• High chemical resistance to strong acid and alkali suspensions

The primary field of application is the partition chromatography of polar substances such as amino acids, carboxylic acids or carbohydrates. The TLC-plates are available as glass plates, POLYGRAM^® polyester sheets and ALUGRAM^® aluminium sheets.

• Fiber length (95 %) 2-20 µm
• Average degree of polymerization 400-500
• Specific surface according to Blaine 15000 cm²/g
• ≤ 20 ppm Fe, 6 ppm Cu, 7 ppm P
• Dichloromethane extract ≤ 0.25 %
• Residue on ignition at 850 °C ≤ 1500 ppm
• Available with or without fluorescent indicator (UV 254)