Thin Layer and Column Chromatography, Lab Report Example

Objective

The goal of the experiment was the evaluation of organic pigments by means of the application of column chromatography in addition to a collection of elution incorporating hexanes, acetones and methanol.

Background

Chromatography is a perspective applied in order to divide a compound of two or more ingredients founded on the physical qualities. Chromatography can be applied a means of purifying the compounds on a minute scale in addition to an evaluation of mixtures. Chromatography optimizes of the differences regarding the physical characteristics. These qualities include the point of ebullition and the polarity of the ingredients in order to perform a separation of the compounds during the mobile and stationary stages. The stationary stage is consistently rinsed with the mobile stage.

Furthermore, as time elapses the aggregated compounds will become separated into its constituent ingredients founded on the physical qualities of the components. In addition, an evaluation may be conducted in order to observe if some specific components demonstrate enhanced adhering properties during the mobile stage or the stationary stage.

Procedure

The apparatus for conducting the column chromatography was established. A compacted wad of cotton had been placed into the column by means of the application of air pressure originating from the fume hood. A minute quantity of sand and subsequently hexane had been aggregated into the column tube. The hexane had been combined with silica in a flask. Afterward the mixture had been aggregated to the column tube.

An additional amount of hexane had been added due to the mixture becoming desiccated in a short interval. Next the mixture endured the rinsing process once again in order to perform a rinsing of the column tube. The process had been conducted repetitively for the silica and hexane.  In addition, the procedure had been performed for a third trials for the comprehensive rinsing of the column tube. The mixture was applied and ceased when required in order to maintain the column tube and the sand in a horizontally inclined position. A tier of hexane and sand had been aggregated into the column once again. The mixture endured the process until the liquid had emerged at the upper tier of the sand.

TLC

A ratio of ten percent and twenty percent of the mixture of the ethyl acetate and the hexane had been formulated a transferred into 50 ml graduate cylinders which were volumetrically labeled. There had been the slicing of two TLC plates which also had been delineated by pencil at a measurement point of 0.5 cm. In the application of micro capillary tubes, two benzo pyrene drops which had been inscribed with a label “B” and two biphenyl drops had been insert4ed on the numbers to which they had been delegated on the TLC plates. Each of the reactants had been delated to one drop for each of the plates. An observation of the TLC plates had been conducted under ultraviolet luminescence.

Two flasks for developing had been obtained and a minute layer of the mixture which totaled to 10% and 20% of the thin layer chromatography had been aggregated to the flasks. In the application of tongs, the TLC plates had been inserted into the developing flasks following the rinsing of the percentage of the solution with the mobile and stationary stage. The proportion had been 10% for the flasks containing the 10% developing solution and 20% for the flasks which contained the 20% developing solution. The samples had been placed under a watch glass. As the solvent attained a level which had been half of a centimeter beneath the top plate, the TLC plates were extracted. The flask containing the solvent was inscribed upon with a label.  An additional observation of the TLC lights had been conducted. Any of the discolorations on the plates had been identified by marking with a pencil.

New Sample

The mixtures which had been labeled as “A” and “B” were transferred into the column tube. A minute quantity of hexane had been added in order to perform cleansing by means of pipet. The flask which had been labeled #1 had been inserted into the column tube. Each of the flasks had been transferred while the mixture was being prepared. The process had been performed during seven trials.

Caution

Caution had been taken when handling the hexane, acetone and methanol. Eye protection in form of goggles had been used. In addition, rubber gloves had been used during the experiment.

MSDS

Hexane was applied in the experiment. The linear formula for hexane is CH₃(CH₂)₄CH3. Hexane is a hazardous material. Eyre shields, face shields and gloves should be used (Sigma Aldrich 1).

Chemical Disposal

The chemical which had been used in the experiment which included the chromatography tube, hexane, acetone, and methanol solvents, in addition to the reactants had been placed in waste disposal containers for removal after the experiment.

Discussion

The components of the partition of the mixture within the two phases in an explaining of the coefficient of the partition pertinent to chromatography, where the components’ coefficient x is equivalent to the proportion of the saturation of x during the stationary phase over the saturation of x during the mobile phase. As a result, the following relationship and formula is demonstrated.

KP (x) = [x] stationary& [x] mobile.

The coefficient of partition can be reviewed and measured. In the event that the coefficient is greater than the value of one, it is inferred that x endured for a longer interval during the stationary phase as it had been rinsed during the mobile phase. In the event that the coefficient has a value less than one, x endeared for a longer period of time in the mobile phase and had been rinsed with the stationary phase. The value of less than one is indicative that x has a greater affinity toward the mobile stage than the stationary phase.

There are a number of kinds of chromatography and all apply the partition coefficient as a method of detailing the separation of a compound during the mobile and the stationary phases. However, these compounds can be distinguished by the kinds of phases and the approaches of point liquid. In the column chromatography, the mobile phase is fluid and the stationary phase is usually conducted with a polar solid which does not become dissolute during the mobile phase. The stationary solids wh8ich are applied are SiO_{2 (}silica gel) and Al₂O₃ (alumina), in a finely pulverized form

Conclusion

The goal of the experiment had been to separate an organic pigment by the means of thin layer chromatography. As the results demonstrated, the pigments had been separated and the discolorations were marked by pencil. The temperature could have been a factor in the experiment. In addition, the amount of time that the reactants were exposed to the substrate could have been another factor of uncertainty.