PHOTODYNAMIC SENSITIZERS ASSAY - RAPID AND SENSITIVE IODOMETRIC MEASUREMENT

A rapid, sensitive and simple spectrophotometric method for the detect ion of O-1(2) produced by photodynamic photosensitizers in slightly ac id and air-saturated aqueous solutions has been developed. The method is based on the reaction of O-1(2) (produced by photodynamic processes ) with I- in the presence of ammonium molybdate as a catalyst. The rea ction product I-3(-), proportional to O-1(2), is followed spectrophoto metrically at 355 nm. Several ways of avoiding interference with other oxidizing compounds, either present before or produced during the irr adiation, are described. The method could be used to measure the effic iency of water-soluble photodynamic photosensitizers.