Filter paper in the chemical experiment is a relatively important supply, so, we want to be skilled in the use of filter paper, which is a necessary procedure in each of our chemical experiments. Filter paper most filter paper is made of cotton fiber, so we have to use different methods for different purposes. Moreover, because it is made of fiber, it has innumerable holes in its surface through which liquid particles can pass, whereas larger solid particles cannot.
This property permits the separation of mixed liquid and solid substances. What’s more, the filter paper is a kind of filter tool commonly used in chemical laboratories. It is usually round in shape and made of cotton fiber. In addition, paper chromatography is based on filter paper as an inert support. Filter paper fiber and water have a strong affinity, can absorb about 22% of the water, and 6~7% of the water in the form of hydrogen bond and cellulose hydroxyl, in general conditions more difficult to remove, and filter paper fiber and organic solvent affinity are very weak.
Because the cotton fiber in filter paper has a good affinity for water, it can absorb about 22 percent of water, of which 6 to 7 percent is bound to cellulose in the form of hydrogen bonds. In general, it is very difficult to remove. Compared with the affinity with water, the cotton fiber in filter paper has a weaker affinity with organic solvents.
Therefore, in most cases, paper chromatography takes the combined water in filter paper fiber as the fixed phase, while the mobile phase is dominated by organic solvents. When the mobile phase of the organic solvent passes through the sample, the water, and the organic phase will be continuously distributed, and then with the mobile phase constantly moving, the material of various components will be continuously redistributed, further separating and purifying the material. This use of filter paper is common in chemical laboratories. Both water and alcohol can be filtered.
Filtration and filter paper chromatography are two completely different concepts. Filter paper is actually a sieve, but its hole is relatively small, on the packaging box of filter paper have instructions, the size of the aperture. Generally use a medium – hole filter paper. Filter paper does not reach the molecular level unless the molecules are very large, such as high molecular weight polymers. So filtering is generally to remove mechanical impurities.
Chromatography is actually a method to diffuse different substances in the solution in the separation, generally speaking, because different substances on the filter paperdiffusion rate are not the same, with the passage of time, to different parts of the filter paper.
Using filter paper for chromatography is also called paper chromatography. If you know anything about the experiment of separating chlorophyll in biology class, you can use paper chromatography.
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