Inert Support and Matters Needing Attention of Chromatography Filter Paper

Inert Support of Filter Paper

Hawach Scientific filter paper is a common filter tool in the chemical laboratory, the common shape is round, and the common material is cotton fiber. Paper chromatography uses filter paper as an inert support. Fiber and water of filter paper provide strong affinity, which can absorb about 22% of water, and 6~7% of the water is in the form of a hydrogen bond with the hydroxyl group of cellulose.

The affinity of filter paper fiber and the organic solvent is very weak, so general paper chromatography uses the binding water of filter paper as the stationary phase and organic solvent.

Distribution and Purification of Filter Paper

when the mobile phase passes through the sample along with the paper, the solute on the sample point is continuously distributed between the organic phase and the water, and a part of the sample moves with the mobile phase and enters the solute-free zone, and then redistributes again.

Meanwhile, part of the solute enters the stationary phase from the mobile phase. With the continuous movement of the mobile phase, various parts are continuously distributed according to respective distribution coefficients, and move along the mobile phase, so that the material can be separated and purified.
papers used in paper chromatography

Matters Needing Attention in Filter Paper

  1. Purity of Filter Paper:
    • Ensure that the filter paper is of high purity. Any impurities in the paper could interfere with the chromatographic separation or introduce artifacts.
  2. Pore Size and Thickness:
    • Select filter paper with an appropriate pore size and thickness. The pore size affects the separation of compounds, while the thickness influences the flow rate. Choose paper that suits the specific requirements of your chromatographic application.
  3. Wetting and Wet Strength:
    • Consider the wetting characteristics of the filter paper. It should wet uniformly when in contact with the mobile phase to ensure proper capillary action. Additionally, check the wet strength to avoid disintegration during the chromatographic process.
  4. Uniformity:
    • Ensure the uniformity of the filter paper. Irregularities or variations in the paper could lead to uneven chromatographic results.
  5. Handling Precautions:
    • Handle filter paper with clean hands or gloves to prevent contamination. Avoid touching the central area where the sample is applied to minimize the introduction of contaminants.
  6. Storage Conditions:
    • Store filter paper in a clean and dry environment. Humidity or exposure to contaminants can affect the performance of the paper. Follow the manufacturer’s recommendations for storage conditions.
  7. Compatibility with Analytes:
    • Consider the compatibility of the filter paper with the analytes being separated. Some compounds may interact with or adsorb onto the paper, affecting the chromatographic results.
  8. Quality Control Checks:
    • Perform quality control checks on the filter paper, such as testing its efficiency in removing particulates and ensuring it meets the required specifications for the intended chromatographic application.

Some matters should be kept in mind: first, the chromatography filter paper should be close to the inner wall of the funnel; second, the edge of the filter paper should be lower than the funnel edge, filtrate should be lower than the edge of the filter paper; third, the beaker should close to glass rod, glass rod should close to three-layer filter paper, leakage bucket diameter should close to the inner wall of the beaker.

Moreover, filter paper after wetting should stick to the inner wall of the funnel, if there is a gap between the filter paper and the inner wall of the funnel, the speed of filtration will be relatively slow. When the chromatography filter paper is close to the inner wall of the funnel, the filtered liquid constantly flows out from the lower end, thus making the pressure below the filter paper less than the atmospheric pressure above, thus making the filtration faster and smoother.

Furthermore, the funnel tip should be close to the inner wall of the beaker, if the tip of the funnel is not close to the inner wall of the beaker, the speed of filtration will be affected to some extent. And there are other reasons for the turbidity of the filtrate, in which the chromatography filter paper is damaged or the liquid level is higher than the edge of the chromatography filter paper.

In the manufacturing process of Hawach qualitative chromatography filter paper ( such as Qualitative Filter Paper Disc Grade: BIO-1, Qualitative Laboratory Filtration Filter Paper Grade: BIO-2, Qualitative 20 Micron Filter Paper Grade: BIO-4, Qualitative Chromatography Filter Paper Grade: BIO-5, Qualitative Filter Paper Biology Grade: BIO-6), treated with hydrochloric acid and hydrofluoric acid and washed with distilled water, most of the impurities in the pulp are removed. The ash is very little after burning, which complies with international rules in this area. Made of high-quality cellulose, Hawach quantitative chromatography filter paper ( such as Quantitative Medium Flow Filter Paper Grade: BIO-40, Quantitative Ashless Filter Paper Grade: BIO-41, Quantitative Laboratory Filter Paper Grade: BIO-42, Wet Strengthened 10 Micron Filter Paper Grade: BIO-91) is high-grade ashless, and suitable for almost all precipitates. Made under intense quality control standards, all the Hawach quantitative chromatography filter paper will make it ideal for use to meet your needs.