Teaching Flame Photometry with an Affordable, Durable, Instructor-Built Instrument Suitable for Large Chemistry Lab Sections

This experiment engaged students, based on student survey responses, in the application of flame photometry to determine salt concentrations in real-world samples. A simple, affordable flame photometer was developed to make this technique accessible in both general and undergraduate advanced analytical chemistry laboratories. The rugged benchtop device performs reliably under ambient lighting and is well suited for large laboratory sections, where multiple instruments are required. The setup employs a Vernier emission spectrometer, a concentric nebulizer, and a standard Bunsen burner. The nebulizer, constructed from readily available components (PVC stock, HPLC tubing, and fittings), is both easy to construct and durable enough for long-term instructional use. The experiment has been successfully implemented for determining sodium in soy sauce in general chemistry courses and for measuring potassium in seawater in advanced analytical courses. Across both course levels, student-generated results typically showed accuracy within 10% of literature values and relative standard deviations around 5% when the instrument was properly optimized. These outcomes demonstrate the experiment’s instructional value by reinforcing calibration, spectroscopy, and quantitative analysis skills.