Capillary Electrophoresis with Laser-Induced Fluorescence Detection for the Diagnosis of Phenylketonuria: A Versatile Wet or Dry Laboratory Experiment in Upper-Level Undergraduate Analytical Chemistry

Capillary electrophoresis is a powerful separation tool with a wide range of analytes for diverse applications and is compatible with various detection methods. While some more established separation techniques like gas or liquid chromatography are utilized heavily in analytical chemistry laboratory courses, newer commercial capillary electrophoresis instrumentation remains underrepresented in undergraduate laboratories, with the concepts being largely in the realm of lecture alone in analytical chemistry curricula. Despite its proven power and wide application, an undergraduate laboratory experiment utilizing capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) has yet to be published. Here, we present an experiment for third- and fourth-year undergraduate analytical chemistry courses in which the students use CE-LIF to optimize system parameters, analyze the amino acid profile of a mock "patient sample", and use calibration standards coupled with statistical analysis to provide a phenylketonuria (PKU) diagnosis. This experiment is easily adaptable to a dry lab, making this technique available to laboratories without the resources needed to acquire a CE-LIF system. We also demonstrate that the dry lab analysis can be accomplished in an online format, requiring no student presence in the laboratory, which is especially relevant due to recent events concerning the COVID-19 pandemic.