Soxhlet and Randall Extractor

Our Soxhlet and Randall Extractor is a fat extraction system specially optimized to determine crude fat or other components soluble in organic solvents according to the universally known solvent extraction method, including the Soxhlet,Randall and Twisselmann methods.

Its flexibility to analyze a wide variety of samples ranging from food to environmental soil analysis makes our extractor suitable for multiple settings and applications.

SX-6 is designed to guarantee accurate and precise results according to the international standardized methods such as AOAC, ISO, AACC, DIN and EPA.

Recommended applications include the analysis of food, feed, soil, detergents, polymers, paper pulp, fibers, gums, textiles, pharmaceuticals and petrochemicals.

Technical data sheet

Installation Guide

Request a Quotation



  • Designed to sustain many years of laboratory work, fabricated with excellent construction materials, featuring a stainless steel external building.
  • Constant supervision of flow rate.
  • Compatible with the Soxhlet, Randall and Twisselmann methods and a wide variety of samples.
  • 3,5″ colour touchscreen and Wi-Fi connection for analysis of results on RAYPAnet.
  • Multiple programs with icons and audiovisual signals make it easy to follow each phase and the status of the assay.
  • Design with six simultaneous extraction positions.
  • The solvent used, extraction temperature and duration of each stage can be programmed.



  • External housing made of AISI-304 stainless steel painted with epoxy resin.
  • Heating by an electric plate with armoured heater for uniform heat distribution.
  • 56 programs, whose names can be customized in terms of the solvent used, temperature and extraction times in the boiling, rinsing and recovery phases.
  • The screen displays the phase and time remaining of each phase. The transition between phases is indicated audiovisually with specific animations.
  • Includes solvent recovery tanks.
  • Constant supervision of flow rate.
  • A microprocessor controls the equipment which features a
  • 3,5″ LCD display and Wi-Fi connection for analysis of results on RAYPAnet.
  • Manufactured to ensure compliance with AOAC, ISO, EPA and DIN international standards.
  • Supplied with all necessary components, including extraction cartridges, Viton® and EDPM seals, racks, clamps and connection hoses.


The traditional Soxhlet method, invented by Franz von Soxhlet in 1879, is the most popular method for fat extraction. It is a standard procedure that provides good analyte recovery, however the extraction procedure is long (it can last 18-24h) and uses a significant amount of solvent.
Soxhlet extraction consists in placing a previously dried sample inside a thimble made of cellulose and then it is loaded into the extractor, which is connected to a flask containing a solvent and a condenser. The solvent is heated and evaporated, the hot solvent vapor then travels up to the condenser, where it cools and falls onto the sample in the thimble. The chamber containing the sample slowly fills with condensed solvent until, when almost full, it is emptied by a siphoning action back into the solvent flask. During each cycle, a portion of the soluble components in the solvent are extracted. This cycle is repeated several times until all analyte is separated from the sample.
In order to improve effectiveness of Soxhlet extraction, alternative methods that use the same extraction principle but have some improved features have been developed. Randall method, suggested by Edward Randall in 1974, is an example of this improvement as it typically allows the reaction to be four times faster and guarantees solvent recovery. SX-6 extractors can be programmed with different extraction steps according to Randall analysis as seen on this page figure.
Twisselmann extraction, also known as continuous economic extraction requires only one extraction position, between boiling and rinsing. The solvent placed in the extraction cup is heated and evaporated, these vapors pass through the sample and reach the condensation chamber, once liquefied, the solvent falls onto sample and is collected again in the extraction cup. Thus, both vapor and liquid forms of solvent simultaneously and continuously extract all lipid content from the sample. After all analyte has been collected, solvent can also be recovered.

Firstly, the sample is immersed in hot solvent, where absorption of sample fat content by the solvent is continuous by both immersion and reflux.

Secondly, the sample is lifted from condensed solvent contact. In this step, absorption of sample fat content by the solvent is continuous only by reflux.

In the final step, the solvent tank valve is closed and the solvent is collected for future reuse. The fat content is deposited at the bottom of the reaction flask.

ModelSX-6 TS
Externals dimensions L x D x H680 x 330 x 580 mm
Power 1500 W
Voltage*230 V
Weight 46 Kg
Frequency 50/60 Hz
Solvent recovery Up to 80 %
Temperature accuracy±0‚5ºC
Maximum number of samples per test6

*Other voltages and electrical configurations available on request



Extraction thimble (25 units)

Extraction vessel (6 units)