Views: 22 Author: Site Editor Publish Time: 2022-04-25 Origin: Site
ultrasonic is refers to the frequency of 20 KHZ ~ 50 MHZ electromagnetic wave, it is a kind of mechanical wave, need energy carrier - medium - to spread. Ultrasonic in the transmission process there are positive and negative pressure alternating cycle, in the positive phase, the medium molecules produce extrusion, increase the original density of the medium; When the phase is negative, the medium molecules are sparse and discrete, and the medium density decreases.
That is to say, ultrasonic and cannot make a polarized molecules within the sample, but between solvent and sample produce acoustic cavitation effect, leading to a solution of bubbles formation, growth and blasting compressed, so that the dispersion of a solid sample, increase the contact area between the sample and solvent extraction and improve the target from solid phase to liquid phase mass transfer rate.
In industrial application, the use of ultrasonic cleaning, drying, sterilization, atomization and non-destructive testing, is a very mature and widely used technology. The principle of ultrasonic extraction The advantage of ultrasonic extraction of Chinese medicinal materials is based on the special physical properties of ultrasonic. The solid-liquid extraction separation is realized by reducing the force between the target extract and the sample matrix through the rapid mechanical vibration wave generated by the piezoelectric transducer.
(1) Accelerate the motion of medium particles. When the ultrasonic wave frequency is higher than 20 KHz in the continuous medium (such as water), according to huygens wave principle, media particles (including the important effective components of medicinal materials) will be caused to move on the wave front of its propagation, so that the motion of medium particles will acquire huge acceleration and kinetic energy. The acceleration of a particle can be calculated to be more than two thousand times that of gravity.
As the medium particle acts ultrasonic energy on the particle of medicinal ingredients in medicinal materials, it can obtain huge acceleration and kinetic energy and quickly escape from the matrix of medicinal materials and free in water.
(2) cavitation. Spread of ultrasound in liquid medium to produce special "cavitation effect", "cavitation effect" created numerous internal pressure to reach thousands of atmospheres of air-pocket and "blasting" continuously produce strong shock waves in terms of microcosmic effect on traditional Chinese medicinal materials, make the medicinal substance was "bombardment" escape, and the medicinal matrix was constantly denudation, The pharmacodynamic components that do not belong to the plant structure are constantly isolated. Accelerate the extraction of plant active ingredients.
(3) Ultrasonic vibration homogenization (Sonication) makes the action of each point in the sample medium consistent and makes the whole sample extraction more uniform. In conclusion, under the action of ultrasonic field, the pharmacodynamic substances in Chinese medicinal materials not only obtain their own huge acceleration and kinetic energy as medium particles, but also obtain strong external force impact through "cavitation effect", so they can be efficiently and fully separated.
The characteristic of ultrasonic extraction is suitable for the extraction of effective ingredients of Chinese medicinal materials, which is a new method and new technology for Chinese medicine pharmaceutical to completely change the traditional extraction method of boiling water and alcohol precipitation. Compared with water boiling and alcohol precipitation, ultrasonic extraction has the following outstanding characteristics:
(1) No high temperature. At 40℃ to 50℃ water temperature F ultrasonic enhanced extraction, boiling high temperature without water, does not destroy some of the medicinal ingredients in Chinese medicinal materials with thermal instability, easy hydrolysis or oxidation characteristics. Ultrasonic wave can make the plant cell break down the wall and improve the curative effect of Traditional Chinese medicine. (2) Atmospheric extraction, good safety, simple operation, convenient maintenance.
(2) High extraction efficiency. Ultrasonic enhanced extraction of 20 ~ 40 minutes can obtain the best extraction rate, extraction time is only boiled, alcohol precipitation method of one third or less. The extraction volume is more than twice that of the traditional method. Statistically, ultrasound is very efficient at 65 to 70ºC. At 65ºC, the active ingredients of herbal plants are virtually intact.
After the addition of ultrasonic wave (at 65 degrees), the extraction time of plant active ingredients was about 40 minutes. However, the cooking time of the cooking method often takes two to three hours, which is more than three times the ultrasonic extraction time. Extract 3 times per pot, basically can extract more than 90% of the active ingredients.
(3) it has broad spectrum. The vast majority of Chinese medicinal materials can be extracted by ultrasound.
(4) Ultrasonic extraction has little influence on the properties (such as polarity) of solvent and target extract. Therefore, there are many kinds of extraction solvents and a wide range of target extraction substances.
(5) Reduce energy consumption. Because ultrasonic extraction does not need heating or the heating temperature is low, the extraction time is short, so the energy consumption is greatly reduced.
(6) The raw material processing capacity of medicinal materials is large, which can be doubled or several times higher, and the impurities are less, and the active ingredients are easy to separate and purify.
(7) The extraction process has low cost and significant comprehensive economic benefit.