An Interdisciplinary-Complementary Chemical Approach to Effective Evaluation in Undergraduate Laboratory Experiments

Is the reductionist approach to teaching chemical principles in the laboratory adequate for students to make effective evaluations? In this work, using the example of sunscreens, students first assessed the analytical chemistry parameters of the active ingredients, later comparing and contrasting them with organic chemistry information for effective practical chemical evaluation in the laboratory. Students evaluated three commercially available brands of sunscreens by a simple, two component experiment analyzing five SPF values with UV spectroscopy using the Beer-Lambert Law to rate the most efficient sunscreen by analytical determination. To explain the differences in degree of photoprotection for sunscreens with the same SPF values in the three brands, students connected the values of molar absorption constant from Beer-Lambert Law for the UV absorbing active ingredients to their organic chemical structures and composition correlating the concentration and application amount with health and regulatory policy, protection performance, and product price. Responses from survey questions asked after students had completed the laboratory experiment and reviewed the molecular structures and regulatory information indicated that the complementary organic and the interdisciplinary regulatory information accompanying the experimental analysis and characterization positively informed and influenced their chemical evaluation.

Automated summary

Students evaluated the effectiveness of different sunscreens by combining analytical chemistry and organic chemistry knowledge, identifying the reasons for variations in photoprotection levels among sunscreens with the same SPF values.