Optimization of ultrasonic frequency for the improvement of extraction yields of bufadienolides from the Chinese medicine ChanSu by using a novel ultrasonic system

Abstract

Optimization of the ultrasonic frequency for the improvement of extraction yields of bufadienolides from ChanSu was evaluated successfully using an online extraction system, which can convert the ultrasonic frequency information to intuitive waveforms that are easily identified by the naked eye. This can provide the information that can quickly select the optimum ultrasonic frequency to obtain the maximum extraction yields. This work has systematically studied the influence of ultrasonic frequency of 20–84 kHz on the bufadienolides yield, whereas existing ultrasonic-assisted extraction (UAE) uses only one or very few frequency points. The higher bufadienolides yield was achieved at the ultrasonic frequency of 54–55 kHz, which was found to be weakly affected by other extraction parameters such as the type of solvent, solvent to solid ratio, ultrasound power, extraction temperature and particle size. The extraction results, which were converted to the intuitive waveforms by the laboratory virtual instrument engineering workbench (LabVIEW) on a computer, could be easily observed by the naked eye by the real-time monitoring of the product concentration in the treatment tank. Hence, it would be favorable to minimize the time-consuming treatments of samples and the required laborious manual manipulations. Comparative studies between existing methods and the proposed method have been carried out. Results indicate that this method can achieve a higher extraction yield compared with the existing extraction technologies.