Paper Chromatography Lab Report

The stationary phase will absorb or slow down different components of the tested solution to different degrees creating layers as the components of the solution are separated. Chromatography was invented by the Russian botanist, Mikhail Tsvet. Chemists use this process to identify unknown substances by separating them into the different molecules that make them up.

The most polar molecules on a chromatography strip move the least, and the least polar molecules move the most. Out of red dye #40, blue dye #1 and yellow dye #5, the molecules in blue dye #1 have the polarity closest to both isopropyl alcohol, and sodium chloride solutions. Red dye #40 has the most polar molecules, while blue dye #1 has the least polar molecules.

The eluting solvent passed down the column by the gravity and an equilibrium was established between the solute absorbed by the absorbent (silica gel in this experiment) and the eluting solving flowing down. Since the components in the sample had different polarity and they interacted with the stationary phase and the mobile phase differently, the components would be carried by the solvent to a different extent and a separation of the components could be achieved.

The intermolecular forces are pulling the molecules between the stationary phase, the chromatography paper and the mobile phase, the solvent. The molecules of the chromatography paper are trying to pull the molecules to where they are while the molecules of the molecules with them to the top of the paper. 4. Draw a picture of how the chromatography worked. Explain your picture using the following terms: stationary phase, mobile phase and intermolecular forces.

This happens through a process called diffusion. Diffusion is the movement of molecules from a region of high concentration to a region of lower concentration. (McQuade,

Random movement of solute (dissolved particles) and solvent (water molecules) will result in an evenly distributed solution.

The following procedure dealt with a chromatogram. The materials needed are: a pencil, safety goggles, scissors, chromatography paper strip, capillary tube, spinach plant pigment extract, test tube, cork stopper, graduated cylinder, chromatography solvent (alternative isopropyl alcohol), metric ruler, stopwatch or clock with a secondhand, hook/fashioned paperclip, paper towels, test tube rack, and mortar and pestle. First we obtained a strip of chromatography paper and cut it so it would fit inside a test tube (with it barely touching the bottom of the tube). Also, when touching the strip, touch the sides only. Then we attached (firmly) the top of the strip to a hook (or fashioned paperclip at bottom of the cork stopper). Make sure it fits in the test tube. Next we used the pencil to draw a faint line across the strip two centimeters from the bottom tip of the strip. We placed the cork and strip in place, and we put a mark on the test tube one centimeter below the top of the stopper.

The movement of water molecules across a semi-permeable membrane is the process of osmosis. If there is a solute and a solvent, each containing different concentration levels, then the water would move along its concentration gradient until each side of the membrane are equal. The water moves because the membrane is impermeable to the solute and the solute concentrations may differ on either side of the membrane. Water molecules may move in and out of the cell, but there is no net diffusion of water. Water will move in one direction or the other, and this is determined by the solute or solvents concentration levels. If the two solutions are of equal concentrations, they will be isotonic. If the concentrations are unequal, the

Gel-Filtration Chromatography is a commonly used method used in order purify a protein from a mixture, by means of separations. Different biomolecules differ in size, or their molecular weight. In the gel matrix inside the chromatography column, there are gel beads which are porous to allow certain sized molecules to enter. The molecules that are able to enter the pores of the gel, are held in stationary phase and will elute from the column later on, these are usually smaller, to medium sized molecules. Larger molecules that are not able to fit in the pores will elute out of the column first, they are involved in mobile phase where they just go straight through the column without interacting with the gel beads. Smaller molecules will have a higher elution volume, while the larger molecules will have a lower elution volume. The volume to elute the protein is inversely proportional to the molecules size.

In this case, there will be a strong attraction between the polar solvent and polar molecules in the mixture which is passed through the column. But in between the hydrocarbon chains attached to the silica (the stationary phase)and the polar molecules in the solution, there won't be as much attraction. Hence, Polar molecules

As the solvent moves past the spotted mixture, two opposing forces created by the solvent and the adsorbent influence the mixture. Each component can either dissolve in the mobile solvent or remain adsorbed to the stationary adsorbent. This process generates an equilibrium, as some components are adsorbed and others are dissolved and transported with the solvent until they are readsorbed further along the plate. The different tendencies of each component to comply with the subjected forces may result in a successfully separated mixture on the plate.

Diffusion is the passage of solute molecules from an area of high concentration to an area of low concentration (Campbell & Reece, 2005). An example is ammonia diffusing throughout a room. A solute is one of two components in a chemical solution. The solute is the substance dissolved in the solution. The solvent, the other component, is any liquid in which the solute can be dissolved (Anderson, 2002). Diffusion requires little or no energy because molecules are always randomly moving; this is due to their kinetic energy. Diffusion occurs only when there is an imbalance in the areas of

2. As a gaseous mixture travels down the column parts of the sample dissolve into the liquid. There is equilibrium between the gas phase (solution) and the stationary phase (liquid phase). This is what the partition coefficient is based on; it is the concentration of the sample in the stationary phase over the concentration of

The diffusion coefficient, also called ‘diffusivity’ is a parameter that is indicative of the diffusion mobility- that is, it presents a mechanism for measurement for the diffusion speed of a solute’s vapor in a gas. The speed of chromatography is determined by the diffusion speed of the solute in the carrier gas. A molecule evaporating from the stationary phase and proceeding into the stream of gas should be capable of diffusing back into the stationary phase before having to undergo the partitioning process again. It is this diffusion of molecules that set apart the gases. In order to obtain a good separation, the most desired carrier gases are those that come in contact with the column a significant number of times. There is a limit to this however, the more time that the gas is given for radial diffusion (diffusion in the direction of the stationary phase), the more time there is for band broadening (longitudinal diffusion). For this reason there is an optimal gas velocity, where it supplies maximum contact with the stationary phase and minimum band broadening in the gas phase.

Chromatography is a separation technique in which the mixture to be separated is dissolved in a solvent and the resulting solution, often called the mobile phase, is then passed through or over another material, the stationary phase. The separation of the original mixture depends on how strongly each component is attracted to the stationary phase. Substances that are attracted strongly to the stationary phase will be retarded and not move alone with the mobile phase. Weakly attracted substances will move more rapidly with the mobile phase.