Experiment 3 - Chromatography – Analyzing Analgesics by TLC and Isolation of β–Carotene by Column Chromatography Chemicals
1. Acetaminophen (C8H9NO2)
2. Aspirin (C9H8O4)
3. Caffeine (C8H10N4O2)
4. Ibuprofen (C13hH18O2)
In this experiment, several analgesics were analyzed by Thin Layer Chromatography (TLC) and the composition of an unknown tablet was identified. We define chromatography as the separation of two or more compounds or ions by their molecular interactions by either a moving or a stationary phase.1 There are different types of chromatography: Thin Layer Chromatography (TLC), Gas Liquid Chromatography (GC), and Column Chromatography (CC). All of which there two phases: mobile and stationary. Phases can be a solid and a liquid, a liquid and a liquid, a gas and a solid, or a gas and a liquid. The stationary phase is also known as the absorbent. Greater affinity, or attraction, for the mobile phases will move faster and conversely for stationary phases.2 Running a solvent past the absorbent complex in order to remove analytes from the absorbent is known as elution. This process aids in determining affinity.3 The most polar compound is always the absorbent; however, the polarity of the compounds in the mixture in addition to the solvents found in the mixture differs in polarities.
We use chromatography, or more specifically TLC, to determine the relative amounts of components in a mixture. Additionally TLC is utilized to determine the identity of two substances. When utilizing TLC, the ratio of distance traveled by the compound to the solvent is defined as Rf. 1
Column Chromatography, is used in this experiment to separate β-carotene from a mixture. Column Chromatography is utilized for purification of both solids and liquids. Primarily, CC is used to separate and isolate compounds. The similarities between TLC and CC include the utilization of a chamber and UV light to identify the affinity of...