Analysis of Paper-Based Colorimetric Assays With a Smartphone Spectrometer

We report on the adaptation of a smartphone's rear-facing camera to function as a spectrometer that measures the spectrum of light scattered by common paper-based assay test strips. We utilize a cartridge that enables a linear series of test pads in a single strip to be swiped past the read head of the instrument while the phone's camera records video. The strip is housed in a custom-fabricated ca...