CHROMAFIL Membrane filters 0.45 µm for NANOCOLOR refill pack of 50
- £193.89 excl. VAT
- £232.67incl. VAT
SKU - 1222723
91652
SKU -
1222723
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Print PageCHROMAFIL Membrane filters 0.45 µm for NANOCOLOR membrane filtration kit refill pack of 50.
Important technical parameters of filter papers
| Parameter | Description |
| Ash content/ residue on ignition | The ash content is determined in accordance with DIN 54370: 10 g filter paper is weighed after ignition in a platinum crucible at 800 °C. Results are expressed as % of the original paperweight. |
| Dry bursting strength | For determination of the dry bursting strength the paper is clamped over a rubber diaphragm with an area of 10 cm2. The strain on the paper is then increased by applying increasing air pressure, until the paper bursts. The dry bursting strength in accordance with DIN 53113 is stated in KPa. |
| Tensile strength | For determination of the tensile strength, a paper strip (measuring 180 x 15 mm) is subjected to vertical strain by applying increasing weight. The force expended at the moment of tearing represents the tensile strength. Results are expressed in N/15 mm. |
| Thickness | The thickness of a paper is measured with a touch pressure device. Especially for soft and creped papers, it is important that the touch pressure is not too high. Otherwise, the papers are compressed and a falsely low thickness is obtained. |
| Filtration speed | For determination of the filtration speed in accordance with DIN 53137 the duration of flow of 10 mL distilled water through a quadrant-folded, freely suspended filter circle of 12.5 cm diameter is measured. Results are expressed in seconds. |
| Basis weight | The basis weight is determined for a sample of 10 x 10 cm. It is measured in g/m2. |
| Gurley test | The Gurley test measures the time required for filtration of 100 mL air at a water column pressure of 31 mm. The sample has an area of ¼ sq. inch. |
| Wet strength | The wet strength of a paper is a measure for the mechanical stability of a paper in a wet or moist condition. For example, it can be determined as the tensile strength or the bursting strength (see above). |
| Pore size | The retention efficiency of a filter paper is influenced by several factors. Since filter papers are deep bed filters, one usually refers to mean particle retention. |
| Capillary rise according to Klemm | The capillary rise according to Klemm indicates how far a strip of filter paper is moistened in 10 min when vertically dipped with one end into distilled water (20 °C) |
| Particle retention | Particle retention refers to the efficiency of filter papers in retaining certain precipitates. It is characterised by the permeability of the paper for precipitates of iron(III) oxyhydrate, lead sulfate, calcium oxalate and barium sulfate. |
Selection of filter papers
| Application | Recommended filter |
| filter cake ignition and quantitative determination of the residue (gravimetric analysis) | ashless filter papers |
| analysis of the filtrate; it is important that no interfering substances are extracted from the filter paper | ashless filter papers or glass fibre filters |
| mechanical removal of the filter cake from the filter, e.g. with a jet from a wash bottle or with a spatula | wet-strengthened filters, (hardened filter papers) |
| visualisation of small amounts of light precipitates | black filter paper (MN 220) |
| technical filtration or need for large cuts | technical filter papers or thick filter papers |
| retention of very fine precipitates | slow filter papers |
| retention of coarse precipitates and fast filtration | fast filter papers |
| filtration of strongly acidic or strongly basic liquids | glass fibre filters |
| filtration of aggressive liquids (e.g. strong oxidants) | glass fibre filters |
| need for very low metal ion blanks of the filter (e.g. for investigation of air-borne particles) | quartz fibre filters |
| accelerated filtration with constant retention efficiency | creped paper |
| filtration at increased pressure or strong mechanical load (e.g. heavy filter cake). | thick technical filter papers |
| strongly absorbent paper, no special wet strength required | chromatography papers |
Membranes enable a very convenient, fast and economical separation. Often they are also used as a neutral sample support for further analysis. Macherey Nagel's provides an extensive selection on membranes. Their chemical resistance can be seen below.
Chemical Resistance of Filter Membranes
