Glycerine as Solvent for Ultrasonic Extraction
Glycerine or glycerol can be used as purely (100%) or as mixture of glycerine and water or ethanol for botanical extraction. Learn about the advantages of utilizing glycerine as extraction solvent in sonication processes.
Botanical Extraction in Glycerine using Sonication
Botanical extraction is a fundamental process in analytical chemistry, biochemistry, and natural product research, aimed at isolating specific components from complex mixtures. Traditional extraction methods, such as maceration or Soxhlet extraction, often require long processing times and the use of organic solvents, which may pose environmental and health risks. In last decade, ultrasonic extraction has replaced traditional extraction techniques such as maceration, Soxhlet and solvent extraction, since sonication is more efficient, faster, more effective and environmentally friendlier. Besides these benefits of ultrasonic extraction, this technique allows to use the solvent of choice. Ultrasonic extractors can even handle pure vegetable glycerine as a solvent.

UP400ST ultrasonic homogenizer for herbal extraction using glycerine as solvent.
How Do Probe-Type Ultrasonicators for Extraction Work?
Sonicators used for botanical extraction use the power of intense ultrasound. Via the ultrasonic probe, high intensity ultrasound is transmitted into the solvent, where numerous cavitation bubbles occur. The rapid formation and collapse of microscopic cavitation bubbles generate shear forces and intense agitation, localized high temperatures and pressures. These sonomechanical forces effectively disrupting cell walls and facilitating the release of intracellular compounds. This ultrasonically intensified extraction technique offers several advantages, including reduced extraction times, increased yield, and the ability to process thermolabile substances without significant degradation.
Vegetable Glycerine as Extraction Solvent
Vegetable glycerine, a colorless, odorless, and viscous liquid derived from plant oils, is widely recognized for its solvent properties. It is non-toxic, biodegradable, and exhibits excellent solubility for a wide range of organic compounds. As a solvent, vegetable glycerine offers several benefits over traditional organic solvents:
- Safety and Environmental Impact: Glycerine is non-toxic and environmentally benign, making it a preferable choice for green chemistry applications.
- Food- and Pharma-Grade: Vegetable glycerine is available in food- and pharma-grade quality. Being alcohol-free, edible and sweet-tasting, glycerine is an appreciated solvent for extracts designed for food and pharmaceuticals. For cosmetics, glycerine is a well regarded solvent due to its emollient properties.
- Solubility: It can dissolve both hydrophilic and hydrophobic substances, broadening the scope of extractable compounds.
- Stability: Glycerine is chemically stable, which helps preserve the integrity of sensitive compounds during extraction.

Ultrasonicator UIP1000hdT for botanical extraction.
Protocol: Ultrasonic Extraction from Herbal Leaves into Glycerine
In this protocol, we guide you through the steps of ultrasonic extraction of bioactive compounds from herbal leaves into pure glycerine. You can watch the complementary video above to get a visual impression of the ultrasonic extraction process.
You need:
- fresh or dried herbs
- 100% vegetable glycerine
- probe-type sonicator, e.g. the UP400St with sonotrode S24d22L2D
- glass beaker
- dark glass bottle for storage
Step-by-Step Instructions
- Chop the herbal leaves into small pieces (approx. 5x5mm).
- Place the herbal leaves into the glass beaker.
- Add the glycerine. You might let soak the herbs for a few minutes.
- Insert the probe of the sonicator into the beaker. Center the probe in the middle of the beaker and make sure that the sonotrode does not touch the walls of the vessel.
- Set the amplitude to 100% and start sonication.
- Monitor the temperature with the temperature sensor that comes with the UP400St.
- When the temperature rises above the temperature, that you do not want to overstep, you can either pause the sonicator to let the glycerine slurry cool down. You can set a temperature limit in the menu of the UP400St. Additionally, you can place the glass beaker into an ice bath.
- Sonicate for a total energy input of approx. 200-250 Ws/g. (You can set the targeted energy input in the menu of the UP400ST and all digital Hielscher sonicators.)
- After sonication, remove the exhausted plant material from the glycerine by filtration. You can use a strainer, filter paper or a cheese cloth. In order to facilitate the filtration of the viscous glycerine, use vacuum filtration.
Trouble-Shooting and Tips:
The colder the glycerine, the higher its viscosity. Highly viscous liquids require a more powerful sonicator. The 400 watts powerful sonicator UP400St handles 100% glycerine at room temperature sovereignly. If you are using a sonicator with lower power, you might use a glycerine-water mixture (e.g. 50:50 %v/v).
For cold glycerine, an industrial sonicator such as the 1000 watts ultrasound processor UIP1000hdT are ideal to process highly viscous solvents.
Protocol: Extraction of Phytochemicals from Gentian Root
A practical application of glycerine-water mixtures in ultrasonic botanical extraction is demonstrated in the isolation of phytochemicals such as amarogentin from Gentian root in 50% glycerine using the Hielscher UP200Ht sonicator. Gentian root contains bittering flavor compounds that are of interest in the food and beverage industry, as well as in traditional medicine.
Amarogentin offers a 58,000,000 bitterness value and is found in 0.15% concentration in the Gentian root. The bitterness of gentian is characterized by a clean flavor. Offering high potency, Gentian root bittering compounds are valued as a strong flavor compound.
Step-by-Step Instructions for ultrasonic Gentian root extraction using glycerine as solvent
The use of a glycerine-water mixture, combined with the high-performance UP200Ht sonicator, results in a high yield of extracted phytochemicals. The mild conditions of glycerine ensure that the sensitive compounds remain stable throughout the process.
Glycerine and its mixtures with water or ethanol provide versatile solvent options for ultrasonic botanical extraction. Despite the challenges posed by the high viscosity of glycerine, advanced sonication equipment like Hielscher UP200Ht can effectively handle these solvents, ensuring efficient extraction of valuable phytochemicals. The ability to tailor the solvent composition and leverage the power of ultrasonic waves makes ultrasonically-assisted extraction a powerful technique for the isolation of bioactive compounds from plant materials.
Ultrasonically-Asisted Extraction in Glycerine
Combining probe-type ultrasonicators with vegetable glycerine as solvent presents a powerful approach for extraction. The mechanical effects of ultrasonication enhance mass transfer, improving the efficiency of glycerine in solubilizing target compounds. This combination is particularly effective for extracting bioactive compounds from plant materials, such as polyphenols, alkaloids, and essential oils.
Applications for Ultrasonic Botanical Extraction in Glycerine
This extraction technique has promising applications in various fields:
- Pharmaceuticals: Isolation of active pharmaceutical ingredients from medicinal plants.
- Food Industry: Extraction of natural flavors, colors, and antioxidants.
- Cosmetics: Production of bioactive compounds for skincare and beauty products.
- Deep Eutectic Solvents Due to its low cost, high availability, non-toxic nature, non-flammability, and non-volatility, glycerol and glycerol-based deep eutectic solvents are ideal for ultrasonic extraction of polyphenols, offering a highly sustainable solution.
- high efficiency
- state-of-the-art technology
- reliability & robustness
- adjustable, precise process control
- batch & inline
- for any volume
- intelligent software
- smart features (e.g., programmable, data protocolling, remote control)
- easy and safe to operate
- low maintenance
- CIP (clean-in-place)
Design, Manufacturing and Consulting – Quality Made in Germany
Hielscher ultrasonicators are well-known for their highest quality and design standards. Robustness and easy operation allow the smooth integration of our ultrasonicators into industrial facilities. Rough conditions and demanding environments are easily handled by Hielscher ultrasonicators.
Hielscher Ultrasonics is an ISO certified company and put special emphasis on high-performance ultrasonicators featuring state-of-the-art technology and user-friendliness. Of course, Hielscher ultrasonicators are CE compliant and meet the requirements of UL, CSA and RoHs.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
Batch Volume | Flow Rate | Recommended Devices |
---|---|---|
0.5 to 1.5mL | n.a. | VialTweeter |
1 to 500mL | 10 to 200mL/min | UP100H |
10 to 2000mL | 20 to 400mL/min | UP200Ht, UP400St |
0.1 to 20L | 0.2 to 4L/min | UIP2000hdT |
10 to 100L | 2 to 10L/min | UIP4000hdT |
15 to 150L | 3 to 15L/min | UIP6000hdT |
n.a. | 10 to 100L/min | UIP16000 |
n.a. | larger | cluster of UIP16000 |
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Literature / References
- Sumbal Jamshaid, Dildar Ahmed (2022): Optimization of ultrasound-assisted extraction of valuable compounds from fruit of Melia azedarach with glycerol-choline chloride deep eutectic solvent. Sustainable Chemistry and Pharmacy, Volume 29, 2022.
- Jamshaid, S., Ahmed, D. & Aydar, A. Y. (2022): Ultrasound-assisted extraction optimization of polyphenols, flavonoids, and antioxidant compounds from fruit of Melia azedarach using a glycerol-based green deep eutectic solvent. Journal of Food Processing and Preservation, 46, e16657.
- Turrini, Federica; Donno, Dario; Beccaro, Gabriele; Zunin, Paola; Pittaluga, Anna; Boggia, Raffaella (2019): Pulsed Ultrasound-Assisted Extraction as an Alternative Method to Conventional Maceration for the Extraction of the Polyphenolic Fraction of Ribes nigrum Buds: A New Category of Food Supplements Proposed by The FINNOVER Project. Foods. 8. 466; 2019
- Petigny L., Périno-Issartier S., Wajsman J., Chemat F. (2013): Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.). International Journal of Molecular Science 14, 2013. 5750-5764.
Facts Worth Knowing about Glycerine
What is Glycerine? Glycerine, also known as glycerol, is a trivalent alcohol with high water solubility and hygroscopicity. This makes it a versatile solvent in various applications. The viscosity of vegetable glycerine is approximately 1400 centipoise at 20ºC. Glycerine is non-toxic, biodegradable, and recyclable. It is produced from renewable sources, making it an environmentally friendly solvent. Since glycerine is low-cost and highly available, it is used widely in various industries. Being non-flammable and non-volatile, makes glycerine safe in handling and storage.
Glycerine is soluble in water, ethanol, and methanol, which broadens its applicability as a solvent in different chemical processes.
For what Applications is Glycerine used as Solvent?
Glycerine is valued for its diverse applications in both food and cosmetic industries. Using glycerine as a solvent one of its strong application as it offers chemical properties and a high versatility as a solvent.
In Cosmetics and Medicine: In cosmetics and medicine, glycerine is commonly used as an emollient in creams and gel formulations. It acts as a solvent for many poorly soluble substances, enhancing their bioavailability. The efficacy of glycerine in these applications stems from its chemical nature as a trivalent alcohol, which imparts high water solubility and hygroscopicity.
In Food and Beverages: Glycerine serves multiple roles in the food and beverage industry. It acts as a humectant, solvent, and sweetener, contributing to the preservation of foods. It is also utilized as a filler in commercially prepared low-fat foods, such as cookies, and as a thickening agent in liqueurs.
Polyol Properties: Glycerine, a polyol (sugar alcohol), is recognized for being non-toxic, biodegradable, and recyclable. It is produced from renewable sources and functions as a polar protic solvent due to its trihydric alcohol structure. This makes it highly hydrophilic and soluble in water, ethanol, and methanol.
Water Extraction Co-Solvent: Glycerine is an effective co-solvent for water extraction processes, particularly noted for its efficacy in obtaining polyphenol extracts.
What is the Role of Glycerine in Ultrasonic Extraction?
Glycerine, also known as glycerol, is a colorless, odorless, viscous liquid that is widely used as a solvent in botanical extractions. Its unique properties make it particularly suitable for extracting sensitive phytochemicals that might degrade under harsher conditions. This ability of glycerine to preserve the integrity of bioactive compounds, combined with its non-toxic and biodegradable nature, makes it an attractive solvent for pharmaceutical, cosmetic, and food industries. Whilst pure glycerine is often used as extraction solvent, it is also mixed with water or ethanol at varying ratios.
Glycerine-Water Mixtures: Mixing glycerine with water reduces the viscosity of the solution, enhancing its cavitation efficiency during ultrasonic extraction. A typical mixture might consist of 50% glycerine and 50% water, balancing the viscosity and solvent efficacy. This combination is particularly effective for extracting compounds like bittering agents from Gentian root, as demonstrated in ultrasonication processes.
Glycerine-Ethanol Mixtures: Adding ethanol to glycerine creates a solvent mixture with lower viscosity and enhanced solvent properties. Ethanol, being a good solvent for many phytochemicals, helps in the more efficient extraction of compounds while the glycerine component ensures stability and biocompatibility of the final extract.

Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers from lab to industrial size.