CHEM 221 LAB REPORT 2 (EXPERIMENT 2: THIN-LAYER
CHROMATOGRAPHIC ANALYSIS OF COMPONENTS IN COMMON
PAIN-KILLERS) 2025 Concordia University
LAB REPORT
EXPERIMENT 2: THIN-LAYER CHROMATOGRAPHIC ANALYSIS OF COMPONENTS IN
COMMON PAIN-KILLERS
Name: THI HONG LOAN LAI
Student ID: 40293473
CHEM 221 LAB SECTION 53L
, 1. INTRODUCTION:
Thin-layer chromatography, or TLC, is an instrument that we are using in this experiment to
separate, identify, and evaluate complex organic mixtures, such as the active ingredients in a
tablet. The advantages of TLC over other methods include its ease of use, low cost, high
sensitivity, and separation speed.
Using the same principle as extraction, thin-layer chromatography (TLC) separates and purifies
compounds by separating them into two phases according to variations in solute and solubility.
These variations are as follows:
• A thin absorbent substance coated on a thin-layer sheer (TLC plate) is referred to as the
stationary phase. Typically, alumina or silica gel is used because they have polar surfaces
that interact strongly with more polar samples. Under UV light, it can emit green light;
different characteristics of the stationary phase will lead to various mechanisms and uses.
• A small quantity of mobile phase, also known as development solvent, is put in a
chamber with the TLC plate. In this experiment, it is referred to as 200:1 ethyl
acetate/acetic acid.
• Finally, a solute, which is a volatile solvent combined with an unidentified sample, is
visible on a TLC plate as a dark spot under UV light.
To create the chromatography (or chromatographic separation), the compounds were first spotted
on the bottom of the plate using a thin capillary. They were then immersed in a tiny quantity of
mobile phase, which is typically an organic solvent.
The solvent started to move up on the plate, carrying the three standards and the unknown to the
solvent front, which is located at the top of the TLC plate. While the lesser polar component
travels further with the solvent, the more polar component interacts strongly with the polar
stationary phase and only travels a short distance due to the "like dissolves like" in polarity.
Because the compounds had different chemical properties, they were eventually separated. Using
a UV lamp to illuminate the green fluorescent compound on the TLC plate allows us to
determine the sample's travel distance; this process is known as visualization.
Now, the retention factor, or Rf values, are computed by dividing the travel distance of the
solvent by the travel distance of the sample. As a compound's polarity increases, its Rf value
decreases because it will adhere to the adsorbent more and move away from the baseline less.
CHROMATOGRAPHIC ANALYSIS OF COMPONENTS IN COMMON
PAIN-KILLERS) 2025 Concordia University
LAB REPORT
EXPERIMENT 2: THIN-LAYER CHROMATOGRAPHIC ANALYSIS OF COMPONENTS IN
COMMON PAIN-KILLERS
Name: THI HONG LOAN LAI
Student ID: 40293473
CHEM 221 LAB SECTION 53L
, 1. INTRODUCTION:
Thin-layer chromatography, or TLC, is an instrument that we are using in this experiment to
separate, identify, and evaluate complex organic mixtures, such as the active ingredients in a
tablet. The advantages of TLC over other methods include its ease of use, low cost, high
sensitivity, and separation speed.
Using the same principle as extraction, thin-layer chromatography (TLC) separates and purifies
compounds by separating them into two phases according to variations in solute and solubility.
These variations are as follows:
• A thin absorbent substance coated on a thin-layer sheer (TLC plate) is referred to as the
stationary phase. Typically, alumina or silica gel is used because they have polar surfaces
that interact strongly with more polar samples. Under UV light, it can emit green light;
different characteristics of the stationary phase will lead to various mechanisms and uses.
• A small quantity of mobile phase, also known as development solvent, is put in a
chamber with the TLC plate. In this experiment, it is referred to as 200:1 ethyl
acetate/acetic acid.
• Finally, a solute, which is a volatile solvent combined with an unidentified sample, is
visible on a TLC plate as a dark spot under UV light.
To create the chromatography (or chromatographic separation), the compounds were first spotted
on the bottom of the plate using a thin capillary. They were then immersed in a tiny quantity of
mobile phase, which is typically an organic solvent.
The solvent started to move up on the plate, carrying the three standards and the unknown to the
solvent front, which is located at the top of the TLC plate. While the lesser polar component
travels further with the solvent, the more polar component interacts strongly with the polar
stationary phase and only travels a short distance due to the "like dissolves like" in polarity.
Because the compounds had different chemical properties, they were eventually separated. Using
a UV lamp to illuminate the green fluorescent compound on the TLC plate allows us to
determine the sample's travel distance; this process is known as visualization.
Now, the retention factor, or Rf values, are computed by dividing the travel distance of the
solvent by the travel distance of the sample. As a compound's polarity increases, its Rf value
decreases because it will adhere to the adsorbent more and move away from the baseline less.
