Use of ultrasonic baths for analytical applications: a new approach for optimisation conditions

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.