Experiment 4

Chromatography of Commercial Analgesics
Chromatography of Commercial Analgesics
CHEMISTRY
200L
EXPT 4
PAGE 8 - 11
CHEMISTRY
200L
EXPT 4
PAGE 8 - 11

Janna Vernice R. Villalon*, Christian V. Villanueva, Cyd Vincent L. Zamora
Department of Chemistry, College of Science

*Corresponding author; e-mail: janna.villalon@rocketmail.com
Abstract
In analyzing the chromatography of analgesics, thin layer chromatography (TLC) was used. A very thin (micron) film of silica is coated on a glass plate or a sheet of aluminum or plastic. The ingredients of commercial analgesics were characterized in comparison with chromatograms of aspirin, Acetaminophen, caffeine and mefenamic acid. After the TLC was placed inside a UV chromatography box, it appears that the sample analgesic contains D, which is mefenamic acid.
Keywords: Chromatography, Pigments, Analgesics, TLC

Results and discussion
Thin layer chromatography is a useful method of quickly determining the main active ingredients of commercial analgesics containing aspirin (A), acetaminophen (B), caffeine (C) and mefenamic acid (D).
Thin‑layer chromatography involves the same principles as column chromatography, it also is a form of solid‑liquid adsorption chromatography. In this case, however, in a plate of glass or rigid plastic, the solid adsorbent is spread as a thin layer (approximately 250 um). At the edge of the plate, 2-3 drops of solution was spotted at the origin, and the plate is placed in a container, called a developing chamber, with enough of the eluting solvent to come to a level just below the "spot." The solvent migrates up the plate, carrying with it the components of the mixture at different rates. The result may then be a series of spots on the plate, falling on a line perpendicular to the solvent level in the container.
The retention factor (Rf) of a component can then be measured as indicated in the figure below. Retention Factor (Rf) is simply the distance traveled by spot (Solute Front) divided by distance traveled by solvent (Solvent Front).
The Solute Front and the Solvent Front is shown in table 1.1. In figure 1.1, the chromatoplate is shown with the spots and its Rf.
RfSx=distance traveled by spotdistance traveled by solvent × 100

| Dspot | Dsolvent | Rf | Sx | 4.4 cm | 6.0 cm | 0.73 | A (Aspirin) | 3.8 cm | | 0.63 | B ((Acetaminophen) | 3.3 cm | | 0.55 | C (Caffeine) | 1.9 cm | | 0.32 | D (Mefenamic acid) | 4.5 cm | | 0.75 |

Table 1.1

Figure 1.1
It shows in the chromatoplate that the sample analgesic contains D, which is mefenamic acid. The least component is C which is Caffeine.
References
Garcia, C. (2005). Laboratory experiments in organic chemistry. Manila: University of Santo Tomas. http://www.stevens.edu/wit/research/samples/plipsy_organic_chemistry_lab_report.pdf Retrieved Jan 1, 2013) http://www.nbs.csudh.edu/chemistry/faculty/nsturm/CHE301/Thin%20Layer%20Chromatorgaphy%20Experiment.htm (Retrieved Jan 1, 2013)

References: Garcia, C. (2005). Laboratory experiments in organic chemistry. Manila: University of Santo Tomas. http://www.stevens.edu/wit/research/samples/plipsy_organic_chemistry_lab_report.pdf Retrieved Jan 1, 2013) http://www.nbs.csudh.edu/chemistry/faculty/nsturm/CHE301/Thin%20Layer%20Chromatorgaphy%20Experiment.htm (Retrieved Jan 1, 2013)