Transformation of a Classic Column and Thin Layer Chromatography Experiment into a Multioutcome, Discovery-Based Activity (Journal Article)

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Abstract-

A multioutcome, discovery-based column (CC) and thin layer chromatography (TLC) experiment has been designed for introductory organic chemistry. Multiple outcomes were established using commercially available two- and three-component analgesic medications based on acetaminophen, acetylsalicylic acid (aspirin), and ibuprofen. A series of 11 different medications were identified as unknown analgesic mixtures that can be separated using chromatography. The objective of this experiment is to have students use CC to separate an unknown analgesic medication into its individual components, and TLC to evaluate the quality of their separation and to identify the brand name and composition of their medication. This discovery-based experimental procedure requires students to obtain an individual data set for their assigned unknown analgesic-based mixture and then apply their problem-solving skills toward their TLC results to successfully distinguish the composition of their mixture. Student feedback provided evidence that students acquired lab skills related to chromatography, while also improving their understanding and confidence toward CC and TLC, and enhancing their problem-solving and critical thinking abilities. Further, students felt that this discovery-based activity provided a more realistic demonstration of how chromatographic techniques are utilized in the lab, and presented them in a fun and engaging manner. The capability to differentiate the unknown analgesic mixture ensures that students not only develop lab skills for CC and TLC, but also acquire other pedagogical gains common to inquiry-based learning.