How can optimized solid–liquid solvent extraction techniques improve analytical precision?
Solvent extraction is a widely used analytical method for separating and quantifying components from solid or liquid matrices using a suitable solvent. It relies on the solubility of specific compounds in the chosen solvent, allowing selective removal and measurement. A sample is immersed in a solvent, then it is washed off with fresh solvent and the extract collected.
There are several methods of performing an extraction. The traditional Soxhlet method is the best known though it has multiple areas for improvement. The Randall extraction (Used by VELP), also known as hot solvent extraction, is a faster and more efficient variation of the Soxhlet extraction method. Developed by Randall, it reduces the extraction time significantly by operating at higher temperatures and integrating the boiling, rinsing, and evaporation steps into a single process.
How Does the Randall Method Achieve Faster Results in Solvent Extraction?
Perform single or multiple solvent extractions with Randall method, an improvement of Soxhlet technique, as hot solvents are used to speed up the analysis. In fact, the fast solubilization made by hot solvent permits a considerable reduction of the extraction time (approx. 90 minutes).
The extraction is made by immersion of the sample in the boiling solvent, followed by a rinsing phase with cold solvent.
Maximum reproducibility is enoned, as well as a high recovery rate of the solvent used.
SER Series can be used with a wide range of sample types and with a variety of solvents, for increased flexibility.
Immersion
The sample is immersed in boiling solvent for an effective defatting action.
Cleaning
The condensed solvent flows over the sample and through the thimble to complete the extraction process.
Recuperation
More than 90% of the solvent is recovered in the internal recovery tank (SER 158). The glass cup contains the extracted matter.
Applications of solvent extraction
Solvent extraction is widely used for the extraction of different compounds; the most common applications are the determination of crude fat and total fat content, but there are many others.
Food and Feed
- Crude fats
- Total fats
Environment
- Oils and fats in water and wastewater
- Oils and fats in sludge
- Paraffin in wood chips
- Extraction of micropollutants
- PCBs (Polychlorinated Biphenyls)
- Dioxins
- EOX (Extractable Organic Halides)
Agriculture
- Determination of hydrocarbons
- Fat coating of artificial fertilizers
- Coating of fertilizers
- PAHs (Polycyclic Aromatic Hydrocarbons)
- Extraction of cannabinoids
(Photo by nosure cares on Unsplash)
Chemical
- Non-gelled material by polymer crosslinking
- Determination of oil presence in recycled PET
- Resin residues in paper
- Saponified oil and unsaponifiable matter in soap
- Oils and lubricants
- Softeners/Additives in plastic and rubber
- Pesticides (TAPPIT408)
- Phenols
Textile
- Fatty Oil Determination in Feather
- Fat or oil in textiles and synthetic fibers
- Determination of oil presence in leather
- Dye on textile fibers
(Photo by Bozhin Karaivanov on Unsplash)
Products for Solvent Extraction
VELP offers a complete range of solvent extractor systems and hydrolysis unit suitable for qualitative and quantitative extractable matter determinations such as:
- Crude and Total Fat determination in food and feed;
- Fat/Oil extraction in textile fibers, pulp, and paper;
- Sample preparation for PCBs and Dioxin analysis;
- Oil determination in Recycled PET;
- Extraction of cannabinoids;
SER 158 Series – Automatic Solvent Extractor
Fully automatic and cloud-enabled hot solvent extractor, for safety, fast, accurate, and reliable extractable matter determination.
SER 148 Series – Solvent Extractors
Safe and convenient semi-automated extraction system suitable for fat extraction and sample preparation in a wide range of applications in food, feed, environmental, and other industrial segments.
HU 6 – Hydrolysis Unit
Convenient, reliable, and safe hydrolysis unit, for the sample preparation prior to extraction for total fat determination.
Our products
Preliminary Hydrolysis for total fat determination
The VELP Scientifica Hydrolysis Unit HU 6 is the ideal solution for the sample preparation prior to solvent extraction for the determination of the total fat content, in order to free the fat molecules ready for extraction.
This procedure is required in a number of AOAC Official Methods to determine the fat content of food samples such as meat, cheese, seafood, chocolate, cereal flours, etc.
The HU 6 performs hydrolysis in complete safety and handles six samples at the same time in order to maximize productivity.
Fast and safe hydrolysis
The samples are heated in test-tubes in an aluminum heating block offering excellent thermal homogeneity. Hydrolysis is performed in an acidic environment (4N hydrochloric acid) and in some cases also in a basic environment (20% w/v ammonia) for about 60 minutes at a temperature of 170°C. The hydrolyzed sample is then filtered in a glass crucible and washed with warm deionized water to eliminate traces of hydrochloric acid.
The HU 6 is supplied with a vacuum pump that ensure safety thanks to the reduction of acid fumes.
The glass crucible containing the hydrolyzed and washed sample is oven dried before being placed in a desiccator. The crucible is then transferred directly to the SER 158 and SER 148 Solvent Extraction Unit avoiding any possible sample loss and ensuring improved accuracy of results.
The reliable solution for solvent extraction
The SER 148/3 and SER 148/6 can be used to separate a substance or a group of elements from solid and semi-solid samples according to the Randall technique (consisting of Immersion, washing and solvent Recovery).
As for the automatic version SER 158, the main field of application is the determination of the content of soluble products such as fats, detergents, plasticizers and pesticides in food, animal feeds, detergents, rubber and plastic formulas, pharmaceutical products, soil.
The SER 148 Series is a semi-automatic solution with no compromises on operator safety (IP55) and solvent consumption also guaranteeing a limited cost per analysis.
Combined to HU6 Hydrolysis Unit, is possible to use the same crucibles to prevent any possible sample loss between the two units.
Randall Method, Faster Results
Perform single or multiple solvent extractions with Randall method, an improvement of Soxhlet technique, as hot solvents are used to speed up the analysis. In fact, the fast solubilization made by hot solvent permits a considerable reduction of the extraction time (approx. 90 minutes).
The extraction is made by immersion of the sample in the boiling solvent, followed by a rinsing phase with cold solvent.
Maximum reproducibility is ensured, as well as a high recovery rate of the solvent used.
SER Series can be used with a wide range of sample types and with a variety of solvents, for increased flexibility.
Fast and accurate solid-liquid extraction
The SER 158 Series automatic solvent extractors, available in 3- and 6-position models, provide precise and accurate solutions for both quantitative and qualitative extractable matter determination according to the Randall method, analyzing up to 5 times faster than traditional Soxhlet extraction.
The solid-liquid extraction process efficiently removes soluble components from solids through 5 sequential steps. The SER 158 works in compliance with international standards, including s AOAC, ISO, EPA, APHA, UNI.
With robust heating, advanced software, and integrated safety features, the SER 158 ensures reproducible extraction results.
The SER 158 is fully automated to maximize productivity and free operator time. Just Load&Go!
Unparalleled versatility and scalability
The SER 158 Series stands out for its versatility, designed to handle all sample types and sizes with a complete range of accessories and consumables:
- Butyl, Viton, and the exclusive Vaflon seals ensure broad compatibility with the majority of solvents and solvent mixtures.
- 3 different sizes of cups, thimble holders, and thimbles enable precise extraction of minimal sample amounts while reducing solvent use.
- Choose between cellulose thimbles for quantitative analysis and glass fiber thimbles for qualitative analysis.
- Compatibility with HU6 glass crucible to prevent sample loss during transfer.
The SER 158 is a universal solvent extractor and combining up to 4 units enables you to perform multiple applications independently and simultaneously.
Smart and easy to use.
The SER 158’s exclusive 7" ControlPadTM offers a highly intuitive User Interface, simplifying setup and interaction with the analyzer.
Engineered for 24/7 unattended operation, the SER 158 leverages the Load&Go technologies, minimizing the need for manual intervention. The integrated, removable ControlPadTM supports connection with a balance and barcode reader, maximizing automation and ensuring full traceability.
Choose from a library of pre-installed methods, create new ones, and mark your favorites for a fast start-up. The ControlPad™ displays each extraction step in real-time, providing a comprehensive set of information and options.
Results are immediately calculated and stored in the on-board memory. With three USB ports and an Ethernet connection, data can be easily exported to external devices for seamless integration.
