Using the thin layer chromatography the major components of a commercial analgesic tablet will be indentified and purified. The active ingredients of the analgesic used were characterized by comparison with chromatograms of aspirin, acetaminophen, ibuprofen, mefanemic acid, and caffeine through the use of UV chromatography then the Rf value was calculated for each solvent. INTRODUCTION In this experiment, thin-layer chromatography (TLC) will be used to determine the composition of various analgesics.
Chromatography is a technique used to separate and identify individual components in a mixture. Chromatographic techniques make use of the fact that components of a mixture tend to move at different speeds along a coated tube or flat surface. Thin-layer chromatography is one of the easiest of the many chromatographic techniques. A thin layer of a suitable solid substance is coated on a sheet of glass or plastic. A very small sample of the mixture to be analyzed is “spotted” onto the sheet.
By immersing one edge of the sheet in an appropriate liquid developing solvent, the solvent is drawn up the sheet by capillary action, and the compounds of interest are carried along at different rates, effectively separating the components. This is commonly called “developing” the plate. After the plate has been developed, it is examined under ultraviolet (UV) light, which allows you to note the location of the spots.
TLC include the solvent system used to dissolve the compounds, the adsorbent coated onto the TLC plate, the thickness of the adsorbent layer, and the relative amount of the material spotted onto the plate. Under an established set of experimental conditions, a given compound always travels a fixed distance relative to the distance the solvent front travels. This ratio of the distance the compound travels to the distance the solvent front travels is called the Rf value. Rf = distance traveled by the substance distance traveled by the solvent front.
Therefore, on the assumption that there was a solvent system which could sufficiently separate the Rf values of these analgesics on a silicon-coated plate, thin layer chromatography was used to identify which of these exist in the commercial tablet, Ibuprofen Alaxan, by a comparison of their Rf values. This experiment aims to indentify and characterize the major components of commercial analgesic tablets which in this case the assigned tablet was Ibuprofen Alaxan. MATERIALS AND METHODOLOGY I. Preparing the TLC plates Cut a 5×10 TLC plastic sheet.
six mark spots must be placed so that the solvents will be placed properly later on through the capillary, this marks must be 1cm apart and 1cm from the bottom edge of the TLC sheet. II. Preparing the Sample The sample analgesic was triturated with 2ml methanoltoluene it was then decanted and transferred into a vial. The standards that were used were already prepared, the aspirin, acetaminophen, ibuprofen, mefanemic acid, and caffeine. III. Sample Application Using a capillary tube, one end was dipped in the sample solution to allow the solution to enter by capillary action.
On one end, using the index finger block the top-end of the capillary, lightly and then quickly spot it to the mark on the TLC plastic sheet. Using new capillary tubes, repeat the same process for the other spots for all. IV. Sample Developing The TLC plate was carefully placed inside a beaker containing ethylacetate-methanol-aceticacid and covered with a watch glass. A filter paper was also placed inside the beaker. The solvent inside must not reach the spots on the TLC plate. Let the solvent move up though capillary action until it reaches the front mark on top.
Then remove the TLC plate and air dry it. V. Analysis and Documentation Place the TLC plate inside the UV chromatography box. Turn it on and mark the spots you can see using a pencil. Then calculate the Rf value for each corresponding spot. RESULTS AND DISCUSSION The chromatograms of aspirin, caffeine, acetaminophen, ibuprofen, and mefanemic acid, and their Rf values as recorded in Table 1. aspirin| acetaminophen| ibuprofen| Mefanemicacid| caffeine| Sampleanalgesic| 2. 8/4. 1= 0. 68| 2. 4/4. 1= 0. 59| 2. 3/4. 1= 0. 56| 3. 2/4.
1= 0. 78| 1. 3/4. 1= 0. 32| 2. 3/4. 1= 0. 56| Substances: Rf Values: Table 1 As shown in the table above the sample analgesic has the same Rf value with ibuprofen, this thus prove that the active ingredient in the sample, Alaxan, is ibuprofen. Thin layer chromatography is a useful means of quickly characterizing the main active ingredients of certain commercial analgesics containing aspirin, caffeine, acetaminophen, mefanemic acid, and ibuprofen when they do not have many other organic compounds in significant proportions.
In this case, it was determined by thin layer chromatography that in the sample Alaxan’s the most active is the ibuprofen and acetaminophen is can also be found. CONCLUSION Therefore, we conclude that thin layer chromatography (TLC) is one of the best ways to characterize and identify the most active agent in a commercial analgesic. And with the use of the Rf value we can prove that the most active component in our sample, Ibuprofen Alaxan, is the component Ibuprofen and next to it is acetaminophen. So to this we can say that in Alaxan the ibuprofen is the most active component based on the chromatogram.