Fluorescent molecules are compounds that absorb light of one wavelength, then re-emit light at a longer wavelength. This emitted light can be quantified using fluorescence spectroscopy. Molecular and cellular biologists use fluorescent compounds to label proteins, gels, and even cellular organelles. In many ways, fluorescent compounds have revolutionized research in the life sciences.

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The new SpectroVis Plus spectrophotometer/ fluorometer can be used to conduct fluorescence spectroscopy on many compounds, including chlorophyll, fluorescein, and Green Fluorescent Protein (GFP). Sample spectra are provided in the graph below.

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Fluorescence spectroscopy can also be used to teach concepts in chemistry. Fluorescein is a fluorescent molecule that is structurally similar to the pH indicator phenolphthalein. Both compounds are sensitive to changes in pH, but phenolphthalein is not fluorescent. The only difference between these two compounds is a single oxygen atom. Sample spectra are provided in the graph below. A figure is also included that shows the chemical structure of each compound.

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Download instructions for phenolpthalein vs fluorescein demonstration »