Ultraääni Soxhlet-uutto

Ultrasonics improves the conventional Soxhlet extraction. Ultrasonically assisted Soxhlet, also known as Sono-Soxhlet, extraction leads to higher yields and shorter extraction times. Hielscher probe-type sonicators can be easily integrated into any classic Soxhlet extractor setup.

Soxhlet Extraction using Ultrasonication

Soxhlet extraction is a frequently used solid-liquid extraction method used in synthetic or analytical laboratory and is required when a desired compound shows only a limited solubility in a solvent, and the impurity is insoluble in that solvent. In brief, the working principle of the Soxhlet extraction can be described as a solvent-based reflux.
Ultrasound is successfully integrated into Soxhlet extraction to increase yield and to shorten the duration. When the Soxhlet extraction is completed, the solvent is removed (e.g. using a rotary evaporator).

Problems with Conventional Soxhlet Extraction:

The traditional Soxhlet extraction has major disadvantages due to its long extraction duration and the large amount of solvent used. Furthermore a conventional Soxhlet extractor lacks agitation. Agitation is required to accelerate the extracting process. As conventional Soxhlet extractors use large amounts of solvent, the subsequent evaporation and concentration require a lot of energy. The extract quality is often negatively impacted by the long retention time of the extracted compounds in the heated bulb of the Soxhlet extraction setup. Thermo-labile target compounds are decomposed as the material is exposed during the long extraction duration to the heat of the boiling point of the solvent.

Solution: Ultrasonic Soxhlet Extraction

Powerful ultrasound increases the mass transfer between sample and solvent. Thereby, less solvent is required. The extraction duration is drastically shortened so that the extracts are not exposed to long heat exposure. Thereby, unwanted thermal decomposition of the extract is avoided or at least significantly reduced.
Ultrasound can be easily integrated into a Soxhlet extraction setup – either by introducing the ultrasonic horn (probe, sonotrode) into the Soxhlet chamber or by sonication the Soxhlet chamber indirectly through the vessel wall. Ultrasonic Soxhlet extraction – aslo known as Sono-Soxhlet – results in a higher yields within shorter extraction time under milder extraction conditions.

Industrial-scale Sono-Soxhlet and Sono-Clevenger setups with Sonicator UIP1000hdT
(©Vernes et al., 2020)

“Ultrasonication as an extraction method is an efficient technique when compared to reflux methods for extracting trace organics from soils and sediments. Ultrasonic extraction techniques proved to generate comparable or even greater quantities (Song et al., 2002) of hydrocarbons than other techniques of extraction […]. Depending on the type of contaminants and matrix, sonication can have the advantage of faster extraction times. Optimisation of the ultrasonic extraction parameters, including type of solvent or solvent composition, extraction time, sample load, and water content are required many times for more efficient and reproducible extractions (Berset et al., 1999). Ultrasonication techniques usually provide a relatively low cost method, using small volumes of organic solvent without the need of elaborate glassware and instrumentation.”
[Oluseyi et al. 2011]

Advantages of Sono-Soxhlet Extraction

Sono-Soxhlet extraction is a variant of the traditional Soxhlet extraction technique that incorporates high-intensity ultrasound to enhance the extraction process. The Sono-Soxhlet technique offers several advantages, backed by scientific research and studies, which include:

• Increased Extraction Efficiency: Sono-Soxhlet extraction increases the efficiency of extraction by breaking down the cell walls of plant materials or other sample matrices. Acoustic cavitation created by intense ultrasonic waves improves mass transfer and enhances the penetration of the solvent into the sample, thereby increasing the yield of extracted compounds.
• Reduced Extraction Time: Sono-Soxhlet extraction significantly reduces the extraction time compared to conventional Soxhlet extraction. As ultrasound promotes faster mass transfer and diffusion, the extraction of analytes and botanical compounds takes only a short treatment. Shorter extraction duration means higher throughput capacities, too.
• Lower Solvent Consumption: The combination of Soxhlet and ultrasonic extraction results in reduced solvent consumption. This not only contributes to cost savings but also minimizes the environmental impact.
• Application Versatility: Sono-Soxhlet extraction is versatile and can be applied to a wide range of sample matrices, including plant materials, food products, polymers, and environmental samples. Its adaptability makes it a valuable tool in various scientific fields, such as phytochemistry, chemistry and environmental analysis.
• Green Chemistry: Sono-Soxhlet extraction aligns with the principles of green chemistry by reducing waste and energy consumption. Its efficiency and reduced solvent use contribute to more environmentally friendly extraction processes.

These beneficial aspects of Sono-Soxhlet extraction contribute to improved process efficiency, time and energy efficiency as well as environmental-friendliness. The main advantages of Sono-Soxhlet extraction are based on increased extraction efficiency, reduced processing time, lower solvent consumption, versatility, and contribution to green chemistry.
Take advantage of ultrasonically improved Soxhlet extraction and contact us know for more information!

Kirjallisuus / Viitteet