Ultrasonic irradiation effect on porphyrin and its application for quantification of ultrasonic intensity

Abstract

The effect of ultrasonic irradiation on aqueous solution of 5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrin (H 2 tpps 4− ) was investigated at frequencies of 40 and 540 kHz and at 25 °C. The degree of decomposition of porphyrin due to ultrasonic irradiation was estimated from the absorption peak measured by an ultraviolet spectrometer. The concentration of H 2 tpps 4− decreased with irradiation time and a steep decrease in the concentration of H 2 tpps 4− was observed with increasing output power from the ultrasound generator. The decomposition of H 2 tpps 4− was found to be of the first order. In addition, the degree of decomposition of H 2 tpps 4− was correlated with the concentration of NO 3 − produced in water by the ultrasonic irradiation. This work demonstrates that the decomposition ratio of H 2 tpps 4− can work as a measure of the irradiated ultrasonic intensity.