Comparison of different alcohols in a caged lumophore for measuring supersaturated dissolved oxygen

Intense phosphorescence is observed when an alcohol is introduced to an aqueous solution containing 1-bromonaphthalene and a cyclodextrin complex. The enhancement of the phosphorescence intensity of 1-bromonaphalene is related closely with the alcohol’s effectiveness in shielding the photo-excited lumophore from dissolved oxygen. The phosphorescence intensity decreases and the phosphorescence decay rate increases as the dissolved oxygen concentration increases. In this paper, we measure the phosphorescence intensity and decay rate of the complex using different alcohols and explain their respective advantages. By relating the concentration of oxygen to the intensity and the lifetime of the phosphorescence, the dissolved oxygen concentration can be measured. The sensitivities and measurement ranges with the complexes containing different alcohols are compared. Currently, this technique can measure dissolved oxygen concentrations from 0 to 40.2 mM (31,400% saturation). The range of the measurement is 40 times larger than previous studies.