Resumen de Understanding Fluorescence Measurements through a Guided-Inquiry and Discovery Experiment in Advanced Analytical Laboratory
Grazyna Wilczek Vera, Eric Dunbar Salin
An experiment on fluorescence spectroscopy suitable for an advanced analytical laboratory is presented. Its conceptual development used a combination of the expository and discovery styles. The “learn-as-you-go” and direct “hands-on” methodology applied ensures an active role for a student in the process of visualization and discovery of concepts. In this multistep experiment, students start their exploration from the observation of a dark current and the scattered ambient light. Subsequently, they explore properties of the visible light. Signal processing techniques are introduced. After finding the excitation and emission wavelengths for fluorescein, students are able to determine the gross calibration curve. The inner filter effect and spectral shift phenomenon are clearly demonstrated. Using the linear dynamic range of the calibration curve, students then determine the concentration of an unknown. The pH effect on the emission intensity of fluorescence is also studied.
