Simple quantification of ultrasonic intensity using aqueous solution of phenolphthalein

Aqueous phenolphthalein solution under sonication was investigated for use as a chemical dosimeter. The fading time of aqueous phenolphthalein solutio n under sonication depended on the concentration of phenolphthalein and the pH values of solutions. The fading time was correlated to the ultrasonic i ntensity in a reaction vessel that is estimated on the basis of decompositi on of porphyrin. The relation between the fading time and the ultrasonic in tensity for different frequencies is expressed by a single curve. From thes e results, it is indicated that aqueous solutions of phenolphthalein is use ful for simple quantification of ultrasonic intensity for practical use, an d one can regard it as one of the ultrasonic intensity indicators. (C) 2001 Elsevier Science B.V. All rights reserved.