Quantitative Determination of Singlet Oxygen By Laser Deflection Calorimetry

ABSTRACT

A sensitive method for the quantitative determination of singlet oxygen based on a low-cost laser deflection calorimeter (LDC) apparatus is presented. The heat released from the singlet oxygen generation and its nonradiative decay in an aqueous phase causes the formation of a thermally driven refractive index gradient in an adjacent organic phase. This effect, which is proportional to the amount of singlet oxygen generated, is monitored by the deflection of a laser beam. Limits of detection (LOD) obtained were in the sub-μmol level which is one order of magnitude lower than the LOD obtained by measuring the “dimol” emission at 633 run. This method should be specially designed for studying chemical and biochemical processes at interfaces by measuring low amounts of heat released.

Keywords::

• laser deflection calorimetry
• singlet oxygen
• interface