Phosphorescence measurement:

A sample tubes are placed in liquid nitrogen held in a quartz Dewar flask that is then placed in the sample holder known as phosphoroscope show in the below figure.

Fig. : Sample assembly for low temperature phosphorescence measurement

For room temperature measurements a sampling procedure depends on the nature of the analyte. For inorganic salts and oxides of rare earths viz., europium and uranium, that have natural phosphorescence, are used without any pretreatment. A sample is held within a solid sample accessory which fits within the instrument.

Instead, some elements show phosphorescence only while adsorbed onto a substrate like, cellulose, paper, silica, etc. For the measurements of polar molecules of this classification a solution of the analyte is prepared in a appropriate solvent and is placed on the filter paper and thoroughly dried. The analyte adsorbed on the substrate is then used for measurement of phosphorescence. A few times, the addition of heavy atoms like iodine, silver or lead is found to enhance the phosphorescence.