Column Chromatography Lab Report

Thin Layer Chromatography (TLC) is an extremely useful technique for monitoring reactions. It is also used to determine the proper solvent system for performing separations using column chromatography. TLC uses a stationary phase, usually alumina or silica, that is highly polar (standard) or non-polar (reverse phase), and a mobile phase, some solvent whose polarity you will choose. In 5.301, and in most lab applications, you will use standard phase silica plates. You will apply your reaction mixture in solution to the plate then "run" the plate by allowing a solvent (or combination of solvents) to move up the plate by capillary action.

In this column chromatography, acetylferrocene was more polar, therefore was held by the silica gel more tightly and moved through the column more slowly when the eluting solvent was nonpolar hexane. Increasing the polarity of the solvent would move all components faster. That explained when the solvent was switched to the more

Chromatography consists of a compound that does not move in the entire experiment (stationary phase) and another compound that runs through the stationary phase (mobile phase). Thin layer chromatography uses a thin sheet of silica gel as the stationary phase. The chromatography plate is then to be placed vertically inside a chromatography chamber (Thin layer chromatography, NA). Column chromatography works very similar to TLC, but instead of using a thin layer of silica gel, in this case we fill a column with this gel (University of Toronto, NA). Finally, we are looking to calculate the value of Rf for every substance.

In Silica gel chromatograph silica gel is used in chromatography as a stationary phase. In this type of column chromatography, the stationary phase is most often composed of silica gel particles. The silica gel particle sizes can be changed for the achievement of a desired molecular size. Silica gel chromatography separates molecules based on their relative attraction to silica, which is generally greater for more polar molecules than for less polar molecules.

Aim The objective of this experiment was to separate a mixture of two compounds (ferrocene and acetylferrocene) using adsorption column chromatography. Introduction Adsorption column chromatography is a technique that uses a solid stationary phase which is fixed and a liquid mobile phase that moves slowly through the packed column. This technique uses the property of polarity as the compounds have a greater affinity towards the respective phases (either stationary or mobile) which leads the compounds moving at different rates through the packed column and separating from one another.

Brianda Mendez Lab 05 Report Introduction: Thin-layer chromatography (TLC) is a very commonly used technique in synthetic chemistry for identifying compounds, determining their purity and following the progress of a reaction. Thin-layer chromatography or TLC, is a solid-liquid form of chromatography, it involves the distribution between two phases. The stationary phase is a polar adsorbent, it is coated on a glass slide or plastic sheet creating a thin layer of the particular stationary phase. The mobile phase, a liquid or a gas flows through the stationary phase and carries the components of the mixture with it.

In Classical Column Liquid Chromatography, the mobile liquid phase flows slowly through the column by means

The purpose of this experiment was to learn about the analytical method known as chromatography which allows the separation of a mixture into its molecular components. In order to illustrate this technique the pigments found in the leaves of spinach were separated by means of thin layer chromatography (TLC). All chromatographic techniques have one principle in common; a liquid or gaseous solution of sample, called the moving phase, is passed (moved) through an adsorbent, called a stationary phase. With TLC the adsorbent of choice was one of the most common coatings, silica gel, SiO2. This compound is polar, and therefore, is frequently used in the separation of polar substances such as aldehydes, ketones, amines and carboxylic acids.

For this experiment, the liquid-liquid extraction and recrystallization technique were used to separate the three compounds: neutral, acid, and base. They were separated on their solubilities into both polar and nonpolar characteristics. The other technique, liquid-solid extraction is used when adding a solvent to a solid. Therefore, the proper technique for this lab that was used was the liquid-liquid extraction and recrystallization technique.

     In liquid chromatography, the separator is called the column and consists in most cases of a tube filled with porous material called the stationary phase. A liquid, called the mobile phase, flows through the tube between the particles of stationary phase material. A liquid sample is taken from a mixture to be analyzed and introduced to a part of the system that is at elevated pressure. The sample is then transported to a separator by the flow in the system.

This would improve the quality of the chromatograms, as the bands produced would be less faint, as in Chromatogram B, where the bands are only just distinguishable, especially through a photograph. The chromatograms in both the paper and thin-layer chromatography could also be improved by using a larger stationary phase. A larger piece of paper or thin-layer plate would increase the surface area of the stationary phase, and give the mobile phase, made up of solvents, more time to travel up the stationary phase. This would allow the pigments within the sample of plant extract to spread out more, and also give more accurate Rf values. To produce more accurate results and improve the chromatograms produced, the chromatography method could have been repeated three times for each investigation, for example three paper chromatograms with acetone as the mobile phase, and three with the mixed solvents, and then three thin-layer chromatograms with the mixed solvent as the mobile

Thin Layer Chromatograph works using the same principle as all chromatographic methods. In TLC the stationary phase used is a thin layer usually of silica gel or a sheet of material coated in alumina and the mobile phase is a set saturation of any suitable liquid containing the mixture we wish to separate. It is set up so that the stationary phase is upright and placed on a low level of the liquid mobile phase, marking where this liquid reaches with a pencil line, on that pencil line a spot of the mixture to be separated is placed. As the mobile phase is absorbed by the stationary phase, or the TLC plate, the mixture should travel up also separating into its components depending on their attraction to the TLC plate as it rises. It is possible in TLC to use pre coated thin layer sheets or to prepare the sheets

O and C-O bonds are polar and the bond dipole moments don't cancel each other out. Due to this eluent being polar most of the molecules remained with the compound as it travelled up the thin layer chromatography paper. We did not choose Ethyl acetate as the best eluent because most of the Rf , except for caffeine, were very close together in value. This would make it harder to distinguish which active ingredient each compound

The solvents that were used in the column chromatography were hexanes, 75/25 hexanes/acetone solvent, and acetone. The adsorbent used in the column chromatography was alumina, which is polar. All of the pigments moved through the column based on their polarity. Hexanes were used because they are nonpolar due to their hydrocarbon chain and was used as the initial solvent before the extract was placed in the Pasteur pipette. Carotene, which is nonpolar hydrocarbon chain, was the first pigment extracted. The nonpolar solvent was used because it is soluble in the nonpolar carotene, thus moving it through the column quickly. To elute the next pigment of chlorophyll the solvent was the hexane acetone mix. This mixture is slightly more polar because

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.