Chinese medicine analysis process ultrasonic pair extraction
Ultrasound is a high-frequency mechanical wave. The frequency range is 15~ 60kHz, generally higher than 20KHz. It is often used for process strengthening and initiation of chemical reactions. The ultrasonic field mainly provides energy to the system through ultrasonic cavitation, and instantaneous cavitation can achieve a high temperature of 5000~ and a local high pressure of 50MPa. Ultrasound has been used in the degradation of organic matter and the extraction of active ingredients of natural medicines. Ultrasonic extraction speed is fast, and the yield may greatly exceed that of Soxhlet extraction method. It has been selected as a means for sample processing by many traditional Chinese medicine analysis processes. The main characteristics of ultrasonic are:
1. The wavelength is short, and it propagates in a straight line; the attenuation in solids and liquids is smaller than that of electromagnetic waves, and its propagation characteristics are closely related to the properties of coal quality.
2. Energy concentration allows for the formation of higher temperatures, generating intense vibrations, causing vibration waves, cavitation in liquids, etc., resulting in various effects such as mechanical, thermal, optical, electrical, chemical, and biological effects.
From the perspective of chemical engineering, experts proposed four additional effects such as turbulent effect, perturbation effect, interface effect and energy-gathering effect of ultrasonic field. They took the leaching process of curcumin-ethanol aqueous solution as the research object, and studied the influence of ultrasonic field intervention on the leaching rate and extraction rate of solid-liquid system. Compared with heating and mechanical stirring, they found that ultrasonic extraction not only accelerated the kinetic process, but also improved the yield, that is, broke the original equilibrium.
Experts studied the extraction of ultrasound at different frequenciesBaicalinThe effects of components were compared at the same extraction time, when the frequencies were 20, 800, and 1100 kHZ, respectively, the yield of baicalin extracted from the root of traditional Chinese medicine Baicalin was the highest at 20 kHZ. It is believed that the reason is that the ultrasonic cavitation effect at this frequency is strong, and the crushing chemical effect is conducive to the transfer of active ingredients and the mixing of baicalin with water. They further studied the effect of different extraction times on the extraction rate of baicalin at this frequency. There are extreme values in the curve, which may be due to the ultrasonic effect onextractIt has a certain destructive effect.
Experts compared several different methods for extracting baicalin from skullcap: soaking method, ultrasound method, reflux method, and Soxhlet lifting method. They believe that the reflux method for extracting baicalin is fast, simple, and efficient, while the soaking method and ultrasound method have low extraction rates and cannot truly reflect the actual content of baicalin in skullcap. This is different from other literature, and the reason may be that the glycosides decompose under the action of ultrasonic field for a long time. The time and intensity of ultrasonic action require a series of experiments to determine. The ultrasonic generator is relatively noisy, and protection needs to be paid attention to. Industrial application is difficult.
