Principles and applications of luminescence spectroscopy

Advances in instrumentation during the last decade as well as the ease with which the technology could be adapted to a wide variety of assay platforms has truly made luminescence spectroscopy the analytical method of choice in several diverse disciplines of life sciences. The primary reasons for its growing popularity are twofold: the use of nonisotopic labels and its exquisite sensitivity. Analyte concentrations as low as 10(-10) to 10(-12) M can be easily detected, while luminometry can detect biological events at concentrations as low as 10(-18) M. This is in contrast to absorption and NMR spectroscopic techniques, which require, respectively, 10(-8) M and 10(-5) M concentrations of the compound of interest. Furthermore, in several variations of this technology, the measurement itself can be nondestructive and noninvasive. Despite the fact that luminescence spectroscopic techniques provide some of the most sensitive and selective analytical methods, they have not yet been widely used in both basic and applied food research. The only exception to this is the growing popularity of the commercially available ATP bioluminescence kits used routinely for monitoring the cleanliness of work surfaces in the food industry. This review describes some of the relevant basic aspects of luminescence, several popular variations of this technology, and their potential uses in food research.