Chlorophyll, oxygen sensitizer

Dissolved oxygen sensors, pH electrodes, or specific ion electrodes can be fitted, and a fluorometer for petroleum oils was developed from the chlorophyll sensor (sensitivity, 1 /xg of naphthalene/L). A solid-state bioluminescence sensor was developed (18) with a minimum detection of 5 x 10 W equivalent to about 10 quanta/s at 480 nm, sufficiently low for the detection of a single dinoflagellate flash (19). 

In the somewhat special case of chlorophyll-sensitized oxygenation processes, Franck55 proposed a mechanism in which the electronically excited chlorophyll dissociates into a dehydrogenated chlorophyll radical and a hydrogen atom, the latter reacting with oxygen to a hydro-peroxy radical. 

Irradiation of olefins and dienes in the presence of oxygen and various sensitizers produces hydroperoxides and cyclic peroxides. Effective sensitizers include not only high-energy carbonyl triplets, but also low-energy organic dyes such as methylene blue, rose bengal, chlorophyl, and riboflavin. The same species that quench the phosphorescence of these complex molecules also quench their photosensitizing ability. 

---