Teaching, learning, and using spectroscopy with commercial, off-the-shelf technology

The astonishing propagation of sophisticated electronics across the globe has attracted the attention of many for developing disease diagnoses, water purity measurements, and security applications using cellular telephones and the complementary metal oxide semiconductor (CMOS) cameras with which many are equipped. This Focal Point article builds on the theme of using technology already in the hands of students/consumers to teach spectrophotometry and, by extension, to suggest how one might inexpensively develop an instrumental analysis curriculum at extraordinarily low cost. A grating spectrophotometer using a white light-emitting diode (LED) light source, plastic sample cuvette, holographic transmission grating, and any camera that produces JPG files as output is described. Optical characteristics are explained and a sample working curve provided. The raw data for that curve are available as Supplementary Material on-line. The behavior of the "Cell Phone Spectrometer" is inadequate for routine analysis but outstanding for teaching the workings of optical instrumentation components and systems.