Recording Procedure:

Once appropriate sampling procedure has been achieved the sample in principle could be used for the concurrent measurement of fluorescence and phosphorescence as the two emissions occur at various wavelengths. Therefore, the fluorescence emission might cause interference in the measurement of phosphorescence.  This interference could be eliminated through taking advantage of the fact that once the incident radiation is cut off the fluorescence ceases immediately while the phosphorescence emission continues. A mechanical shutter could be used to execute recording of phosphorescence under these conditions.

One generally used mechanical shutter system consists of a revolving could that surrounds a sample and has a little window. The can is so rotated in which while it is opposite the excitation monochromator it permits a short burst of radiation to fall on the sample and instantly cut off. After a certain time delay it permit the radiation emitted during phosphorescence to pass by to the emission monochromator. A schematic diagram of the rotating could mechanical shutter system is displays in Figure.

Figure: Revolving can shutter system for recording phosphorescence and fluorescence from the same sample

Having learnt about the theory of fluorescence and phosphorescence, a species displaying these phenomena, the factors affecting them and the instrumentation needs for their measurement you are equipped to learn about the applications of these phenomena within the next section. Therefore, before that why don't you assess your understanding through solving the subsequent self assessment question.