Session: Analytical Division Poster:

In the sudden pivot to distance learning in 2020, analytical laboratory classes presented a particular challenge. The MICRO project explored the use of paper microfluidics to create chemistry experiments for at-home learning. Paper microfluidic devices are inexpensive and easy to make. The microgram quantities of reagents embedded in the paper offer experimental rigor while minimizing concerns over chemical transport and disposal. MICRO labs were designed to cover quantitative analysis topics including titrations, equilibrium, spectrophotometry, and electrochemistry, while cultivating scientific practices such as experimental design. Over 2,000 students at 20+ different universities have performed MICRO experiments. This presentation highlights the design and implementation of a titration experiment and a Job’s method experiment. The titrator has 13 reaction zones containing different quantities of dried sodium hydroxide. It is used for limit titrations to determine vinegar acidity or cream of tartar Ksp. The logistics of producing 11,000 titrators are described to show scalability for implementation in large lab courses. We also detail the development of a new experiment using Job’s Method of Continuous Variation in a paper-microfluidic format to determine the stoichiometry of a metal-ligand complex. MICRO labs teach authentic scientific practices outside the laboratory environment. These inexpensive lab experiments complement regular lab experiences and may be useful after COVID-19 restrictions are eased.

Paper titrator used in MICRO project, showing color change at equivalence point.

Paper titrator used in MICRO project, showing color change at equivalence point.

Vincent Remcho

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