Why Can’t Chromatography Paper Touch the Sides?

In paper chromatography, filter paper and an extraction solvent are the stationary and mobile phases. The stationary phase is stationary, while the mobile phase is a slowly moving solution that carries the components of a mixture to a distant location where they can be easily visualized. Because the mobile phase is so liquid, it is easy for fingers and other organic materials to contaminate the chromatography paper and give inaccurate results.

Using a coffee filter as a stationary phase

Using a coffee filter as a chromatography stationary phase is a great experiment to try with children. It will give them the opportunity to learn about the chemistry behind capillary action, which is the ability of liquids to flow through other materials. Basically, when water passes through a coffee filter, the ink and water move up the filter until it is completely saturated. The ink then spreads out to color the coffee filter. However, when we use an ink, the ink is a mixture of various colored molecules, which are separated by paper chromatography.

Paper chromatography uses a filter paper as a stationary phase, and it can be used in a variety of ways. One of the most common is Alpha cellulose Filterpaper, which holds the stationary phase. This paper is made of cellulose fiber and is capable of meeting the water molecules in the solvent. Paper coffee filters are also a cheap and convenient alternative to chromatography paper.

Using ethanol as a solvent

You can avoid spilling the ethanol by using a small amount of hexane or water as a solvent. These solvents are similar in solubility, which means they can dissolve one another. The difference between ethanol and water is that hexane is slightly more polar than water. In this way, ethanol will not touch the sides of the paper.

Prepare a beaker with silica gel and a funnel. Pour 18 mL of 95% ethanol into the beaker. Stir the mixture with a glass rod until it forms a slurry that flows easily and is the consistency of batter. Do not overstir the slurry or it may clog the funnel and trap air in the column. When the paper is ready, remove it from the beaker and label it with the solvent.

Using a pen instead of a pencil to draw a start line

In paper chromatography, the start line is marked with a pencil. Ink from pens can dissolve in the solvent, contaminating the chromatogram. The lead of a pencil, however, is made of insoluble graphite. So, drawing the start line with a pencil would be the correct procedure. But a few researchers are unsure about this practice.

To avoid a problem, use a pen to draw a start line on chromatograhy paper. A pencil does not have a lead, which can float in the solvent. Ink is not the best choice because the lead can easily dissolve in the solvent. Furthermore, it will ruin the chromatography paper. A ballpoint pen, on the other hand, will spread the ink all over it.

Using a pencil to draw a start line

There are many reasons not to use ink for drawing a baseline on chromatography paper. Pencil ink is dye and can dissolve in solvent, contaminating your chromatogram. By contrast, pencil lead is usually made of insoluble graphite, making it a suitable choice for drawing the baseline on paper chromatography. Nevertheless, using ink for this purpose is not recommended.

When making a chromatogram, it is important to draw a line above the initial level of the solvent in the column. This initial level may not be correct, and can affect the results of your analysis. Often, you will find the baseline level above the start line, which will hinder your chromatography results. In this case, you can use hydrochloric acid instead.

Using a pencil to estimate the center of a non-circular spot

The first step in estimating the center of a non-circular chromatography spot is to estimate the distance between the spot and the origin of the marker dots. This distance is equal to the distance between the origin of the spot and the front of the solvent. After this measurement, the spot is the center of the non-circular spot. To estimate the center of a non-circular spot on chromatography paper, the best way is to estimate the distance from the origin of the dots to the front of the solvent.

Once you have estimated the distance between the spot and the solvent front, you can start measuring the distance between the two components. Then, use the two distances to calculate the Rf value. For each spot, measure the distance between the front and center of each spot, using the formula in Figure 5. You can then use the Rf value to identify the components.

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What is Chromatography?

If you’ve ever wondered what chromatography is, it’s a technique used in the scientific world to separate mixtures of chemical substances. Its purpose is to separate these mixtures into their individual components for thorough analysis. Chromatography is a versatile technique, with many different forms, including gas, liquid, and affinity chromatography. All of these techniques employ the same basic principles. In this article, we’ll take a closer look at some of the most common types.

Mobile phase

The components of the mobile phase in chromatography are different for each molecule. For example, the polar molecules bind tightly to silica particles, while the non-polar ones dissolve in the mobile phase and elute from the column. The mobile phase contains non-polar solvents, such as acetonitrile or hexane. Both the stationary phase and the mobile phase should be inert to sample constituents, as the presence of both may cause column blockage.

The separation of a sample by chromatography is usually achieved using a thin-layer chromatography method. The stationary phase contains a finely powdered solid adsorbent packed into a thin metal column, which is impregnated by a high-pressure pump. The mixture to be analyzed is injected into the column, and the separation is monitored by a detector. This method can be used for volatile compounds, as the sample molecules can be smaller.

Stationary phase

There are several types of stationary phases that can be used in chromatography. These phases may include gas, paper, silica gel, agarose, and high-pressure liquid chromatography. Some types of stationary phases use similar materials, while others are microscopic polymers. Some use silica gel, while others use a microscopic polymer and an inert solid support. Here are some examples of different types of stationary phases:

The pore size of the stationary phase determines the separation performance of the method. It should be small enough to allow particles of the sample to pass through it, such as cannabinoids or plant proteins. For instance, cannabinoids are small and will require a smaller pore size than plant proteins. This is why so many chromatography techniques involve different types of stationary phases. While they are different, they all serve the same purpose.

Elution conditions

Elution conditions in chromatography are the steps used to elute a sample after binding to a target protein. The conditions for elution depend on the type of chromatography being performed. Most commonly, the elution conditions are decreases in the concentration of the eluent, which can be stepwise or continuous. A decreasing gradient of ammonium sulfate is the most common elution condition, as it concentrates target proteins and allows for their purification. Other elution procedures involve reducing eluent polarity, adding chaotropic species to eluents, and altering the pH.

The concentration of a solute in the elution gradient can be plotted along the migration coordinate of a chromatogram. Plotting the concentration of a solute along this migration coordinate will provide the peak of that particular solute. Elution profiles of a solute in a chromatogram are shaped in the form of a bell curve, a normal curve, or an error curve, and collectively they are known as Gaussian.


Chromatography is a method of separation that is widely used in the chemical industry. Environmental testing laboratories use chromatographic methods to identify trace amounts of pesticides and toxins in water and waste oil. The Environmental Protection Agency uses chromatography to monitor air and water quality. Pharmaceutical companies use chromatography to produce high-purity materials and to test extracted compounds for contaminants. Chromatography is an important analytical tool, and it is used to prepare large quantities of pharmaceutical products.

Chromatography uses two phases to separate analytes. The stationary phase contains adsorbent and a polar or non-polar solvent. The mobile phase moves from one side of the stationary phase to the other. These phases separate substances by varying retention times. Chromatography has several applications, including determining the concentration of a given substance in blood, urine, and other fluids. Here are some of the most common applications:


Chromatography was first invented by the Russian botanist Mikhail Tsvet in the early 1900s. Tsvet’s chromatography method separated plant pigments by passing them through a column packed with calcium carbonate. The method gained widespread application in the 1930s and 1940s. The Nobel Prize-winning invention of partition chromatography in 1948, by Archer Martin and Richard Laurence Millington Synge, paved the way for broader use of gas chromatography. And during the 1960s, high-performance liquid chromatography was developed for different applications.

Chromatography has a long history of improvement and sensitivity. Scientists have improved chromatography by developing new methods and focusing on the fundamentals. Today, there are more sophisticated methods available, but the original method was developed in 1903.

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