Utilization of time-resolved spectroscopy in the study of photosensitized reactions

Time-resolved optical and photothermal methods used for the detection of transients (above all the triplet states of a photosensitizer and singlet oxygen) in photosensitized reactions are described. Individual types od measurement and the calculation of basic photophysical data (quantum yields, life time of transients, etc.) are shown on the example of tetrakis(sulfophenyl)porphyrin which is used in the Czech Republic as a sensitizer for photodynamic therapy of tumours. The possible use of these methods in the study of complex systems of importance for biology and medicine is discussed.