In this experiment thin layer chromatography is used to identify compounds In | Course Hero

 

thin layer chromatography lab report discussion

the TLC plate. In this experiment, thin layer chromatography is used to identify compounds. In order to allow for good separation of all three compounds for correct identification, a solvent-pair was used. The solvent was chosen to be 95% hexanes and 5% ethanol. The hexanes allows for separation of the polar and non-polar compounds and the ethanol allows for the polar compounds to rise up the %(28). Thin layer chromatography (TLC) is a chromatography technique used to separate mixtures.[1] Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose (blotter paper). Mar 26,  · Thin Layer & Column Chromatography By: Lisa Mickey. Introduction Thin layer chromatography (also known as TLC) is the physical separation of a mixture into its individual components by distributing the components between a stationary phase (the porous TLC plate) and a mobile phase (the solvent that moves through the stationary phase and carries the material that needs .


(PDF) THIN LAYER CHROMATOGRAPHY | Mark Buluma Eugine - zellebrss.tk


Thin layer chromatography also known as TLC is the physical separation of a mixture into its individual components by distributing the components between a stationary phase the porous TLC plate and a mobile phase the solvent that thin layer chromatography lab report discussion through the stationary phase and carries the material that needs to be separated.

The driving force to separate components is capillary action. This method can be used to determine how many different components usually non-volatile are in a sample. Column chromatography is a method to physically separate all of the components also usually non-volatile of a mixture.

The driving force to separate components is gravity. Both of these methods work based on polarity differences between components in a sample. In order to perform thin layer chromatography, seven porous plates needed to be obtained that were in good condition with no chips or cracks. These plates functioned as the stationary phase. With pencil, two lines were drawn on each of the seven plates.

One line was drawn 3 mm from one end, and the other line was drawn 12 mm from the other end. A very thin capillary was obtained and dipped into this solution.

The capillary was not held to the plate, but rather just tapped, so the dot of the orange solution on the plate did not have a diameter of more than 3 mm. At this point, seven different solvents needed to be prepared for each of the seven plates and thin layer chromatography lab report discussion in a beaker. Solvent 1 was 5 mL of petroleum ether.

Solvent 2 was a mixture of 5 mL of petroleum ether and 0, thin layer chromatography lab report discussion. Solvent 3 was a mixture of 4 mL of petroleum ether and 1 mL of ethyl acetate.

Solvent 4 was a mixture of 3 mL of petroleum ether and 2 mL of ethyl acetate. Solvent 5 was just 5 mL of ethyl acetate. Solvent 6 was just 5 mL of diethyl ether.

Solvent 7 was just 5 mL of dichloromethane. Each of the seven plates was placed in a different beaker with a different solvent. The plates were labeled 1 through 7, thin layer chromatography lab report discussion, based on the solvent in which they were placed.

Each of the seven beakers was covered in order to prevent evaporation while the solvents soaked up the plates, thin layer chromatography lab report discussion. They were then removed and observed under the UV light.

Each observed spot under the UV light was circled in pencil. Each plate, once again labeled 1 through 7 in order, appeared as shown:.

In order to perform column chromatography, a mixture of 0. This left only a dry, orange powder for the experiment.

After a week passed the only the orange powder was left, the column chromatography apparatus was assembled. A column containing a fritted disk and a stop cock was assembled with two clamps to stand vertically in a fume hood.

The column was assembled as to allowed for a 50 mL Erlenmeyer flask to fit under it for collection. A funnel was also thin layer chromatography lab report discussion in the top of the column. The three Erlenmeyer thin layer chromatography lab report discussion to be used for collection of components of the sample were pre-weighed.

They all weighed in at The two mobile phases to be used to separate the components were prepared. The first mobile phase, or eluent, was a mixture of 30 mL of petroleum ether and 1. The second mobile phase, thin layer chromatography lab report discussion eluent, was just 20 mL of ethyl acetate.

This formed a white slurry. The column was tilted and the slurry was added to the column. The remaining silica was poured into the column. No air bubbles were present in the silica gel. Some of the eluent was allowed to drain into a beaker since over 15 mm of eluent was over the silica gel.

The draining was stopped when about 4 mm of eluent was over the silica gel. At this point, the orange powder was added to the column and the draining was allowed to begin again.

The first eluent was continuously being pipetted into the column in order to prevent the silica from drying. As eluent was being added, gravity pushed the first band of orange down the column.

When the first band reached the fritted disk, the first Erlenmeyer flask for collection was placed under the column.

The first eluent continued to be added until all of the first band of the sample was collected in the first Erlenmeyer flask. It took about 10 minutes for the first orange band to move down the column and be collected. Once this first band was fully collected, a new Erlenmeyer flask was placed under the column for collection.

An orange band lighter in color than the previous band was collected in this flask. A white band containing neither component of the sample appeared in the gel. Below the white band was the lighter orange band being collected in the second Erlenmeyer flask. Above it was another darker orange band containing the component of the sample to be collected in the third Erlenmeyer flask.

When the remainder of the orange band below the white band was collected, the eluent needed to be changed to the solvent containing just ethyl acetate. This was what caused the final band to start moving down the column. As the third orange band, approached the fritted disk, the third Erlenmeyer flask was placed under the column to collect the final component of the sample.

After all three samples were collected, three TLC plates were collected. A thin capillary was dipped in each of the samples. With pencil, two lines were drawn on each of the three plates. The capillary was not held to the plate, but rather just tapped, so the dot of the solution to be tested on the plate did not have a diameter of more than 3 mm. The mobile phase, or solvent used for TLC on each of the three plates was a mixture of 4 mL of petroleum ether and 1 mL thin layer chromatography lab report discussion ethyl acetate.

The solvent was allowed to soak each of the plates to the end line, and then the plates were removed and observed under the UV light. Pencil was used to circles the marks that appeared on the plates under the UV light. The plates were observed the first fraction being on the left, the second fraction being in the middle, and the third fraction being on the right as follows:.

Based on the observations made under the UV light, the second fraction collected actually contained the same component as the first fraction. The second and first fractions were combined into one Erlenmeyer flask. The two Erlenmeyer flasks containing the two different components of the sample were left in a drawer for a week to dry.

The following week the melting points were tested for each of the two dried components. The results show that polarity of the eluent is the deciding factor as to how far a component of a sample will travel on a TLC plate. If the mobile phase is very non-polar, the non-polar components of the sample will travel farther up the TLC plate than the polar components. If the mobile phase is very polar, thin layer chromatography lab report discussion, the polar components will travel farther up the TLC plate than the non-polar components.

Petroleum ether is very non-polar and ethyl acetate is polar. Diethyl ether is polar and dichloromethane is also polar. None of the seven plates had all four spots resolve under the UV light. When the mobile phase was strictly petroleum ether, the spot did not move at all on the TLC plate. As ethyl acetate was added in higher concentration to petroleum ether as the mobile phase, in general, more movement was observed in the spots.

Also, a lot of movement was observed when diethyl ether and dichloromethane were used as the mobile phases. In general, this shows that the components making up the sample were more polar than non-polar, but each had a different polarity from the other.

The eluent that worked best was solvent 3. This was a mixture of 4 mL of petroleum ether and 1 mL of ethyl acetate. The eluent was polar enough for separation, but not too polar like for plates 4 through 7 where only one spot could be observed.

Only plates 2 and 3 showed more than one spot, but they still only showed three spots instead of four. This could be because of the eluents not being properly covered, so they evaporated during the experiment. Also, some plates could have been left in the mobile phase for too long and not taken out at the right time. The Rf values for the spots on plate 2 were 0, thin layer chromatography lab report discussion. The Rf values for the spots on plate 3 were 0.

Since none of the seven plates had four resolved spots, the TLC spots could not be assigned a substance. The results show that polarity of the eluent is the deciding factor as to how quickly a component of a sample will travel down a column for a collection in column chromatography. If an eluent traveling through a silica gel is less polar, thin layer chromatography lab report discussion, the less polar component will travel down the gel quickly for collection, while the polar component stays stationary in the gel.

A more polar eluent was necessary to start the more polar component of the sample to travel down the gel for collection. The first and middle fractions collected were azobenzene. Since there was originally 75 mg of azobenzene present in the sample and only 0.

Thin layer chromatography lab report discussion there was originally 75 mg of meta-nitroaniline present in the sample and only 0. Browse Documents. Column Chromatography thin layer chromatography. Leave a reply Cancel reply Your email address will not be published. Comment Name Email Website.

 

Thin Layer Chromatography Lab Report - words | Study Guides and Book Summaries

 

thin layer chromatography lab report discussion

 

the TLC plate. In this experiment, thin layer chromatography is used to identify compounds. In order to allow for good separation of all three compounds for correct identification, a solvent-pair was used. The solvent was chosen to be 95% hexanes and 5% ethanol. The hexanes allows for separation of the polar and non-polar compounds and the ethanol allows for the polar compounds to rise up the %(28). Mar 26,  · Thin Layer & Column Chromatography By: Lisa Mickey. Introduction Thin layer chromatography (also known as TLC) is the physical separation of a mixture into its individual components by distributing the components between a stationary phase (the porous TLC plate) and a mobile phase (the solvent that moves through the stationary phase and carries the material that needs . Thin layer chromatography (TLC) is a chromatography technique used to separate mixtures.[1] Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose (blotter paper).