12.14 : 荧光和磷光：仪器

Fluorometers and spectrofluorometers are two instruments used to measure molecular fluorescence, each featuring a light source, filters or monochromators, sample cell, transducer, and signal processor.

Fluorometers use low-pressure mercury vapor lamps as the excitation source, employing absorption or interference filters to select excitation and emission wavelengths.

Conversely, spectrofluorometers use a high-pressure Xenon arc lamp and a monochromator to select excitation and emission wavelengths.

Both devices detect fluorescence through a transducer, such as a photomultiplier tube or a charge-coupled device, converting the signal into an electrical measurement.

Molecular phosphorescence is measured using a phosphorimeter, which accounts for the delay between excitation and phosphorescence emission by employing out-of-phase rotating choppers.

These choppers alternately block fluorescent emission during excitation and the excitation source during phosphorescent emission measurement.

Here, the sample is either dissolved in an organic solvent mixture and frozen at liquid nitrogen temperatures or immobilized on a solid substrate to prevent deactivation of the excited state by external conversion.