TLC Practical: Identifying Unknown Metal Ions Using TLC - Essay Example

This research will begin with the statement that TLC is a laboratory technique used to monitor the progress of a reaction, to identify the compounds present in a substance under investigation or to determine its purity. The main attractive feature of TLC is that it requires only small quantities of the substances being analyzed. The molecules of the different substances are separated physically without the occurrence of any irreversible chemical reaction. Being inexpensive to perform and versatile in nature, TLC is increasingly being used in a wide array of applications ranging from forensics and radiopharmaceuticals to environmental pollution studies.

 In this study, the technique is used to find out whether the given two unknown substances contain Fe(III), Co(II) or Cu(II) and how the Rf for the three ions can be calculated. 2. Methods Principle: In TLC, the compound gets distributed between a solid fixed phase adsorbent substance coated over a thin glass or plastic plate known as the TLC plate and a liquid mobile phase which moves over the stationary solid phase. The compound is placed on the starting point towards the bottom of the TLC plate, which is then placed in a developing chamber.

Due to capillary action, the molecules of different chemicals in the compound get drawn up to different extents, depending on their polarity. When the solvent moves over these molecules, they will either stay with the solid phase or accompany the mobile phase, the more similar the physical properties of the chemicals are to the mobile phase, the more will be their tendency to move away with the mobile phase. Procedure: The following steps have to take as detailed below:- Sample application 1.

First of all put on put on the labcoats, safety goggles and the gloves for protection as a safety measure. 2. Ensure that the following materials, namely, the TLC Plate, pencil, Pasteur pipettes, beaker, glass rod, and measuring cylinder are available for use in the experimental procedure. 3. Ensure and verify that the following chemicals/reagents, namely, Unknown 1 and 2, 0.2M solutions of FeCl3, CuCl2 and CoSO4, the chemical reagents of 6Mnitric acid, 5Mhydrochloric acid and acetone necessary for preparing the elution mixture, and developer ammonia are available and ready for use. 4. With the pencil, draw a line 2cm away from the bottom edge of the TLC plate and leave an equal distance from the edges.

Apply the samples of Unknown 1,2 and the standards FeCl3, CuCl2 and CoSO4 keeping a distance of 4cm between them on the line by means of the Pasteur pipettes as small drops which form spots so that they are equidistant from the bottom edge of the TLC plate. Let the drops dry by allowing 2-3 minutes to pass before more drops are applied again by touching the TLC plate with the capillary lightly and quickly. 5. Meanwhile, prepare the Elution mixture by mixing 3drops of acetone,10 drops of HNO3(6M) and 5 drops of HCl(5M) in the beaker.