1. OBJECTIVE
Through this experiment, you will develop practical skills for performing the thin layer chromatography technique through the analysis of clove essential oil.


At the end of this experiment, you should be able to:

perform thin layer chromatography (TLC) of clove essential oil;

recognize the main steps of TLC analysis for compound identification;

recognize the methods used to reveal and visualize compounds separated by CCD, including ultraviolet light and colorimetric reagents;

determine the retention factor of the main component (eugenol) present in clove essential oil and compare it with data from the literature;

use the applications of the CCD technique in the context of pharmaceutical sciences;

prepare the technical report or practice report.

2. WHERE TO USE THESE CONCEPTS?
The TLC technique is widely used for the qualitative characterization of compounds, as it presents good reproducibility, operational simplicity, low cost and reduced analysis time. In the scope of the analysis of compounds of plant origin, CCD is applied in pharmacognosy and quality control laboratories of raw materials. In this way, CCD can be combined with compound isolation techniques, which enables monitoring and certification of isolation, as well as quality monitoring and identification of possible adulterations in raw materials of plant origin. Furthermore, as it is a pharmacopoeial method, the application of CCD is not restricted to the qualitative analysis of raw materials of plant origin, as it is also used in tests to identify compounds of synthetic origin, impurities and toxins. . In organic synthesis laboratories, CCD is used in reaction monitoring, indicating the formation of products and consumption of starting reagents.


3. THE EXPERIMENT
The experiment consists of identifying the main compound of clove essential oil (Syzygium aromaticum) using thin layer chromatography. This technique allows the separation of volatile compounds from the essential oil through the application of a silica gel chromatoplate (stationary phase) and organic solvents (mobile phase). The compounds present in the oil interact with the stationary and mobile phases and are eluted throughout the chromatoplate. At the end of the process, the displacement points of the compounds are visualized in the form of bands under ultraviolet light or by applying colorimetric reagents. Each compound will present a specific retention factor, and the comparison of this factor, together with the color of the band, with the eugenol standard allows us to infer the presence of this major compound in clove essential oil.


4. SECURITY
In this practice, a lab coat, safety glasses and gloves will be used to avoid direct contact of solvents with the skin and eyes. All reagents that generate irritating and toxic gases, such as toluene, dichloromethane and ethyl acetate, must be handled with care and inside the fume hood. Likewise, the elution of solvents by the chromatoplate must be carried out inside the fume hood.


5. SCENARIO
The practice will be carried out in a pharmacognosy laboratory. Before starting the analysis, you must be properly dressed, separate the necessary material (solvents and glassware) and organize them under the bench. The handling of volatile and potentially toxic solvents, such as dichloromethane, toluene and ethyl acetate, is carried out inside the fume hood.