The use of spectroscopic instrumentation such as single-beam spectrophotometers and spectrofluorometers within the undergraduate curriculum enables the collection of high-quality data in the teaching laboratory setting, provides students hands-on experience with their operation, and also serves to reinforce the understanding of spectrochemical phenomena. Unfortunately, the expense of these major pieces of equipment can be cost-prohibitive for many programs, and even if such instruments are available, throughput concerns may also limit their use within a large-sized upper-level teaching laboratory. Roanoke College is a private four-year liberal arts college located in Salem, VA, and our Chemistry/Biochemistry programs are accredited by ACS and ASBMB. In this work, we describe our experience implementing three-hour laboratory exercises where students construct their own fully-functional low-cost spectroscopic devices within our Biochemistry and Instrumental Analysis courses, using designs adapted from the chemical literature and ones we have developed ourselves. Specifically, students in these courses construct their own single-beam UV-Vis spectrophotometers for the quantification of the vitamins B9 (folic acid) and B12 (cyanocobalamin), and also construct their own spectrofluorometer optimized for the detection of the reduced form of nicotinamide adenine dinucleotide (NADH), which is then used to obtain the Michaelis-Menten kinetic parameters K<sub>m</sub> and k<sub>cat</sub> for the enzyme lactate dehydrogenase. While each of these devices costs less than $50 to build, they perform well, generating data similar to that provided by commercial-grade instrumentation, and in the case of the spectrofluorometer, also generate kinetic parameters consistent with the known accepted values obtained from the chemical literature. In this work, we describe our experience with the design, construction, and implementation of these devices. We also discuss learning goals, provide actual student data, and present an assessment of student learning.

Implementing low-cost, student-constructed spectroscopic devices within the upper-level undergraduate chemistry laboratory curriculum

ACS Spring 2022

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