How to Use Filter Paper

Because the cotton fiber in the filter paper has a good affinity with water, it can absorb about 22 percent of the water, in the form of a hydrogen bond with cellulose water has 6 to 7 percent. In general, it is very difficult to remove. Compared with the affinity with water, the affinity between the cotton fiber in filter paper and the organic solvent is weaker.

Therefore, in most cases, the paper chromatography method takes the bound water in the filter paper fiber as the fixed phase, while the mobile phase is dominated by the organic solvent. When the mobile phase of the organic solvent passes through the sample, the water, and the organic phase are continuously distributed. Then, as the mobile phase keeps moving, the substances of various components are continuously redistributed, further separating and purifying the substances. This use of filter paper is commonly found in chemical laboratories.

Before use Quantitative Ashless Filter Paper Grade: BIO-41, Quantitative Laboratory Filter Paper Grade: BIO-42, Quantitative Roll Filter Paper Grade: BIO-43, we should know How to Use the Filter Paper first.

How to use filter paper

In the experiment, the filter paper is often used together with filter funnel and brinell funnel. Fold the filter paper into a suitable shape before use. The higher the folding degree of the filter paper, the higher the surface area it can provide and the better the filtering effect. Place the glass rod of drainage on the multi-layer filter paper, force evenly to avoid the damage of the filter paper.

Before using the filter paper, the filter paper must be sprayed with water before it can be used. Because dry filter paper not only has poor filtering effect, but even when the sample volume is small, it will be sucked away by the filter paper, which will affect the experimental results.

For different samples, students can use different sizes of funnels. Sometimes, if there are too many particles in the sample, we can use a funnel connected to the hose to increase the filtration speed. Sometimes there are too many samples, not only affecting the results of the experiment, but even filtering the samples is very difficult. At this time, consider changing another filter paper.

When folding the filter paper, the more creases are better; because the sample contacts the filter paper, the area is relatively large, which increases the filtration efficiency. However, too many creases may damage the filter paper. Therefore, it is recommended to fold the filter paper into a “star” shape.

Filter paper operation process

1. Fold the filter paper in half, twice in succession, and fold it into a 90° center Angle shape.
2. Place the folded filter paper in three layers on one side and open one layer on the other side to form a funnel.
3. Put the filter paper into the funnel. Pour some water into the mouth of the funnel.
4. Place the filter paper funnel on a filter funnel, such as a ring on an iron stand, and place a beaker or test tube to receive the filtrate at the neck of the funnel, with the tip of the funnel neck resting on the wall of the receiving container.
5. When injected into the funnel need to filter the liquid, right-hand hold drip beaker, left hand holding a glass rod, glass rod bottom on tight funnel three-layer on the low side, make close to the glass rod at the top, to filtrate body along the flow at the top, and then tilt the glass rod, momentum into the funnel, flow to the liquid in the funnel, liquid level should not exceed the height of the filter paper funnel.
6. As the liquid passes through the filter paper and flows down the neck of the funnel, check to see if it is flowing downstream along the sides of the cup to the bottom. Otherwise, you should move the beaker or turn the funnel so that the tip of the funnel is firmly attached to the wall of the cup so that the liquid can flow slowly down the inner wall of the beaker.