Sonoluminescence for Water and Other Organic Compounds

Sonoluminescence involves trapping a gas bubble at a sonic antinode's location in a resonance mode of a cell. Ultrasonic waves, which consist of compression and rarefraction cycles, produce these cavitation bubbles in aqueous solution, which collapse violently and adiabatically with an extremely high temperature up to 5000°C and pressures of about 500 atm, theoretically. This bubble expands and collapses emitting a brief amount of light. This phenomenon is very complex and difficult to predict a priori. Through our experiments with water, the preferable resonance frequencies at which the bubble can form and be visible are between 26.1 and 27.9 kHz. Also, to enhance light emission from the bubble, Argon was purged into the solution and several cameras such as digital, film, and infrared were used to detect the sonoluminescence. In recent experiments with ultrasonic irradiation of aqueous solutions with Pharmaceutical and Personal Care Products (PPCPs) it was noticed that the sonoluminescence system could be used as a potential analytical technique of trace amounts of these molecules. It was observed that the maximum voltage amplitude vs. frequency measured by the instrument was sensitive to low concentrations of these contaminants. Preliminary results for caffeine in different concentrations indicate that the resonant peak in the frequency range of 47.5-48.1 kHz for caffeine solutions not only diminishes almost 0.5 volts but also show us a relationship as we increase the frequency . Ongoing work includes the study of the reproducibility and the validation of this technique with other organic compounds as acetaminophen and degassed water. Keywords: sonoluminescence, ultrasound, cavitation (*) Corresponding author E-mail: soraya00987@yahoo.com