1. Sample pretreatment
Drying and crushing: Plant materials (such as lavender, ginseng, etc.) are dried and crushed to 20-60 mesh (particle size affects extraction efficiency).
Weighing: Accurately weigh the sample (usually 1-50g, adjusted according to equipment capacity).
2. Choose a solvent
Polar components (polyphenols, polysaccharides): water, ethanol (30-70%), methanol, etc.
Non polar components (essential oils, lipids): n-hexane, petroleum ether, ethyl acetate.
Proportion: The ratio of material to solvent is usually 1:10~1:30 (w/v), which needs to be optimized according to literature or experiments.
3. Instrument settings
Frequency: commonly used 20-40kHz (low frequency suitable for large molecules, high frequency suitable for small molecules).
Power: Generally 500W, excessive power may damage the components.
Temperature: Set the water bath temperature (usually 25-60 ℃ to avoid degradation of thermosensitive components).
Time: 10-60 minutes (prolonged time may lead to oxidation).
4. Start extracting
Place the sample and solvent into an extraction tank (made of glass or stainless steel) and place it in an ultrasonic bath.
Turn on ultrasound and observe the state of the solution (cavitation produces tiny bubbles).
5. Filtration and concentration
Filtration: Use filter paper or centrifuge (3000-5000rpm, 5 minutes) to remove residue.
Concentration: Vacuum concentration using a rotary evaporator or freeze-drying (for thermosensitive components).
6. Save
Extract should be refrigerated (4 ℃) or frozen (-20 ℃) in the dark to prevent oxidation.