Fluorescence is sometimes forgotten as an analytical technique, relegated to the bottom of the spectroscopy food chain below absorbance, Raman, and FTIR. Yet it offers up often hidden information about material composition, the presence of contaminants or tags, conformation of molecules or the environment in which the active fluorophore resides.
Presence of a fluorophore can be identified with a single peak, while its concentration can be correlated to the intensity of the fluorescence signal. Shifts in center wavelength can indicate a change in structure, environmental factors, or proximity to an acceptor fluorophore via FRET (Forster Resonance Energy Transfer). Sometimes it is an absence of or reduction in fluorescence that yields an answer. And as a delayed emission of light, the lifetime of fluorescence conveys additional information about the fluorophore – its nature or environment. In fact, this is the principle upon which our oxygen sensors are based.
Assays are another powerful way to harness fluorescence for diagnostic purposes, labeling a specific type of molecule or cellular structure and washing the excess marker away prior to detection. Fluorescent tags also can be used to ensure authenticity of fuels or other high-value goods. As diode-array spectrometers increase in sensitivity and more novel variants of traditional fluorescence techniques boost signal levels, compact spectrometers are even beginning to encroach on the traditional ground of complex optical filter trains and PMT detection used in biomedical instrumentation.
Whether employed as a stand-alone technique or blended with others (as in the case of phosphorescence of gemstones emitted concurrently with Raman spectra), fluorescence offers many ways in which to probe the world around us.
- Modular Spectroscopy Tools for Measuring Intrinsic Protein Fluorescence
- Laser Fluorescence Detects Adulterated Honey
- Fluorescence of Edible Oils
- Identifying Natural and Synthetic Gems
- Ensuring Document Security
- Fluorescence of Cutting Oils
- FRET for Mercury Detection in Fish