Detection singlet oxygen

Elimination of the above-mentioned difficulties can be facilitated by the application of sensor methods of detecting singlet oxygen. 

However, the CL method also has shortcomings, such as the inefficiency of CL reactions. We have considered ways to improve CL detection. Thus during 02 detection with CL, correcting CL was considered. To implement this concept, ]02 was measured by FCLA in a photodynamic reaction to achieve correction. We have previously reported that the CL probe, FCLA, which can selectively detect singlet oxygen and superoxide.7 Here CL is measured and analyzed at different probe concentrations and a method of making the detection precise is discussed. 

A fairly efficient method of selective detection of active forms of oxygen by means of sensors is the preliminary separation of their mixture with the aid of filters designed for the purpose, filters that vigorously de-excite this or that form of oxygen. It has been mentioned in Section 5.4 that freshly atomized films of Ag efficiently absorb O-atoms from the gaseous phase, mildly de-excite 02 molecules. To de-excite the singlet oxygen molecules proper, use should be made of filters with... 

Therefore, the application of sensors made it possible not only to detect and identify the molecules of singlet oxygen emitted during photosensibilization by dye molecules but to understand several peculiarities of redistribution of the energy of electron excitation and transfer to solids, as well. 

Emission from dimols of singlet oxygen may be detected by photomultipliers used for measurement of chemiluminescence from hydrocarbon polymers with a maximum spectral sensitivity at 460 nm. The above scheme, however, requires the presence of at least one molecule of hydrogen peroxide in close vicinity to the two recombining peroxyl radicals and assumes a large heterogeneity of the oxidation process. 

Moan, J. and Wold, E. 1979. Detection of singlet oxygen production by ESR. Nature 279 450 151. 

Y. Mikata, S. Takagi, M. Tanahashi, S. Ishii, M. Obata, Y. Miyamoto, K. Wakita, T. Nishisaka, T. Hirano, T. Ito, M. Hoshino, C. Ohtsuki, et al., Detection of 1270 nm emission from singlet oxygen and photocytotoxic property of sugar-pendant [60]fullerene, Bioorg. Med. Chem. Lett., 13 (2003) 3289-3292. 

HTAC cationic micelles also markedly enhance the CL intensity of fluorescein (FL) in the oxidation of hydrogen peroxide catalyzed by horseradish peroxidase (HRP) [39], However, no CL enhancement was observed when anionic micelles of sodium dodecyl sulphate (SDS) or nonionic micelles of polyoxyethylene (23) dodecanol (Brij-35) were used (Fig. 9). CL enhancement is attributed to the electrostatic interaction of the anionic fluorescein with the HTAC micelles. The local concentration of fluorescein on the surface of the micelle increases the efficiency of the energy transferred from the singlet oxygen (which is produced in the peroxidation catalyzed by the HRP) to fluorescein. This chemiluminescent enhancement was applied to the determination of traces of hydrogen peroxide. The detection limit was three times smaller than that obtained in aqueous solution. 

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