Lab 1: Identification of Analgesics using Thin Layer Chromatography by Carla Scott

Objective: To identify the purity of analgesics/prescription drugs using TLC.

Introduction:

The purpose of this laboratory experiment was to identify the purity of certain analgesic products and/or prescription drugs. This technique is commonly used during Crime Scene Investigations to examine and verify the presence of drugs that may have played a role in the crime. Crime scene investigators often use tests similar to this to determine whether an analgesic or prescription drug was used in foul play. In this particular experimental protocol 7 samples of analgesics were used along with thin layer chromatography plates to determine the presence and purity of the samples. A UV lamp was later used to verify their presence.

Materials: Samples 4 & 6 (1 % solution) ethyl acetate and acetic acid were used as solvents. Iodine and and UV lamp were used to identify spots placed by capillary tube. TLC plates made up of Si, were cut into 25 x 5 cm plates (using a ruler) and placed inside a beaker with a watch glass on top.

Procedure: Using a pencil, a line was drawn about 1 cm from the bottom portion of the chromatorgraphy plate. A capillary tube was then used to place spots on the TLC plate above the line previously drawn. Next, the plate was place in a beaker containing ethly acetate or acetic acid (dependent upon the trial) and a piece of filter paper and covered witha watch glass Once the TLC plate was placed into the beaker the solvent vapors completely saturated the plate it was removed and placed on a piece of wax paper to dry. After the plate dried it was placed under a UV lamp and observed. The plate was then placed into a beaker containing iodine.

Results/Data: Figure 1. TLC of Samples 4 & 6

Our results are indicated as follows:

In Figure 1, sample 4 had an R/f value of 0.60

In Figure 1, sample 6 had an R/f value of 0.61

Discussion & Conclusion:

In this experiment the goal was to use Thin Layer Chromatography to determine the presence of analgesic materials and how pure it is. The Rf value calculated from sample 4 it is determined that the substance was pure. The Rf value calculated for sample 6 was 0.61. This value concludes that the substance in this sample was pure as well.

By: Carla Scott