Filter Paper Chromatography, Classification, And Use Notes
Filter paper is frequently used in many different experiments and today HAWACH would like to talk about the filter paper chromatography, classification, and use notes.
Filter paper chromatography
Filter paper chromatography uses filter paper as an inert support. The filter paper fiber has a strong affinity with water and can absorb about 22% of water, and 6 to 7% of the water is hydrogen-bonded to the hydroxyl group of cellulose, which is difficult to remove under normal conditions. The affinity of filter paper fibers and organic solvents is very weak, so the general paper chromatography actually uses the binding water of filter paper fibers as the stationary phase and the organic solvent as the mobile phase.
Partitioning is continuously performed between water and organic phases. Part of the sample moves with the mobile phase and enters the solute-free zone. At this time, it is redistributed, and part of the solute enters the stationary phase (water phase) from the mobile phase. Various parts are continuously distributed based on the respective distribution coefficients, and move along the mobile phase, to make the material separated and purified.
Filter paper classification
Generally, filter paper can be divided into qualitative and quantitative. In the application of analytical chemistry, the residue collected on the filter paper after the separation of inorganic compounds by filtration to separate the precipitate can be used to calculate the loss rate during the experiment. After the qualitative filter paper is filtered, more cotton fibers are generated, so it is only suitable for qualitative analysis. In the production of quantitative filter paper, the pulp is treated with hydrochloric acid and hydrofluoric acid and washed with distilled water to remove most impurities in the paper fiber.
So there is little residual ash after burning, and it has almost no effect on the analysis results, which is suitable for precise quantitative analysis. After ashing, the ash amount is less than 0.0009%.
Filter paper is a filtering tool commonly used in chemical laboratories. The common shape is round and mostly made of cotton fibers. HAWACH can provide both the round and square filter papers. Round filter paper has conventional specifications 70, 90, 100, 125, 150, 180, 55, 47, 185, and also the unconventional sizes of 240, 270, 300. For the square sizes, there are two specifications, 60×60 and 41×45. Welcome to contact HAWACH (hawach.com or email@example.com)to learn more details.
Notes before the use of filter paper.
Filter paper is a scientific tool that can effectively filter media and can be divided into two types. Qualitative analysis filter paper generally has a large amount of residual ash compared with quantitative. It is only used for general qualitative analysis and for filtering sediment or suspended matter in solution, and cannot be used for mass analysis. No matter for the qualitative or quantitative filter paper, there are some notes that should pay attention to before use.
1. In general, it uses natural filtration, with the filter paper body and the ability to retain solid particles, to separate the liquid and solid;
2. Because the mechanical strength and toughness of the filter paper are both poor, try to use less filtration to filter. If the filtration speed must be increased, the filtration failure will be prevented to prevent the filtration. When the air pump is filtered, it can be stacked in the funnel according to the pumping force. Put 2~3 layers of filter paper, when vacuuming filtration, in the leak. First pad a layer of dense filter cloth, then put filter paper on it;
3. Filter paper is best not to filter hot concentrated sulfuric acid or nitric acid solution.