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In this work, the potential of reagent generation assisted by ultrasonic irradiation was evaluated for Cr(III) oxidation and arsine formation. Free radical formation by sonolysis of aqueous solutions was evaluated. The sonication of an aqueous solution saturated with CCl4 leads to chlorine radical formation while the irradiation of water in the presence of metallic zinc leads to hydrogen production. The low relative standard deviations of the proposed procedures indicate that the method can be applied for analytical purposes.

Optimisation conditions for obtaining maximum cavitation intensity in ultrasonic baths are proposed using a simple and fast method. Parameters such as water volume, temperature, detergent concentration, horizontal and vertical positions, number of tubes in the bath, sonication time and bath water substitution were studied. The results obtained for both baths studied (Neytech and Cole-Parmer) lead to the following conditions for maximum cavitation intensity: 1 L of water at room temperature, 0.2 % (v/v) of detergent, central position on the bottom of the tank. Only one tube at a time should be used inside the bath during the ultrasound application. The cavitation intensity was linear with the sonication time up to 10 minutes and the water substitution during the sonication improved reproducibility. This system using continuous water change makes possible the sonication of 6 consecutive samples, without changes in the water volume.