About the Soxhlet Extractor Operation Steps – The Role of The Filter Paper

The soxhlet extractor is a device for laboratory extraction thimbles developed based on the classic Soxhlet extraction technology. This equipment has a reasonable design, stable function, high accuracy, labor-saving operation, and time-saving.

Components of Filter Paper

The Soxhlet extractor consists of three main parts, condenser, extraction bottle, and extraction tube. A siphon pipe and a connecting pipe are arranged on both sides of the extraction tube. All joint parts should be tight without leaking. The tested sample is packed in a degreased filter paper bag and placed in the extraction tube when they are to be extracted. Add petroleum ether to the extraction bottle, and then heat the bottle. After the petroleum ether is vaporized, it will rise from the connecting pipe into the condenser, and the condensed liquid drops into the extraction pipe to extract the lipids in the sample. The petroleum ether dissolved in the crude fat flows into the extraction bottle through the siphon, when the liquid level of petroleum ether in the extraction tube reaches a certain height. The petroleum ether flowing into the extraction bottle continues to be heated to vaporize, rise, condense, and drip into the extraction tube, and so on, until the extraction is complete.

Cellulose Filter Papers 20 Micron Filter Papers

Soxhlet extractor steps

Open the package and check whether the instrument and accessories are complete and damaged. Move the host to the workbench, connect the water inlet pipe on the back of the instrument to the faucet, and lead the water outlet pipe to the sewer. Pay attention to the interface. Note that it must be fastened with a clamp or cable tie to prevent the water pipe from falling off.

1. Make the filter paper disc into a filter paper tube corresponding to the size of the extractor, and then put the sample to be extracted into the filter paper tube and load it into the extractor. Note that the filter paper cartridge should not only be close to the wall of the device but also be easy to pick and place. (A loop of cotton thread can be placed on the filter paper cartridge to facilitate the removal of the filter paper cartridge after extraction.) The height of the extract cannot exceed the siphon tube, otherwise, the extract cannot be fully soaked by the solvent, which will affect the extraction effect.
The extracted material should not leak out of the filter paper tube, so as not to block the siphon tube. If the sample is light, use absorbent cotton to press the sample.

2. In the Soxhlet extract

or, add the extraction solvent and zeolite to the extraction flask (if there are no zeolite, glass beads or broken porcelain pieces can be used, the purpose is to prevent bumping).

3. Connect the flask, extractor, and reflux condenser, connect the condensed water, and heat. After boiling, the solvent vapor enters the condenser tube from the flask, and the condensed solvent flows back into the filter paper cylinder to extract the sample. It will carry the extracted material and flow into the flask from the side siphon if the solvent reaches a certain height in the extractor. In this way, the solvent circulates in the instrument and concentrates the substances to be extracted into the flask below.

Here is an example of common applications of Soxhlet extractors-extraction of crude plant alkaloids.
Make a cylindrical filter paper tube with filtration filter paper, weigh 10g tea leaves, pound the tea leaves with a mortar, put them into the filter paper tube, fold and seal the open end, and put it into the extraction tube. Install the 150 ml round-bottomed flask on the electric heating mantle. Put in 2 zeolites, measure 100 mL of 95% ethanol, pour it into the flask from the extraction cylinder, install the Soxhlet extractor, turn on the power, and heat to reflux for 2 hours.

When the liquid level of the refluxed ethanol in the extraction cylinder is slightly higher than the top of the siphon of the Soxhlet extractor, the ethanol in the extraction cylinder is siphoned and all flows back to the flask. It will reflux again, siphon, and make records. After siphoning for 5-6 times, when the color of the extraction liquid in the extraction cylinder becomes very light, it means that most of the extract has been extracted. Stop heating, remove the electric heating mantle, and cool the extraction liquid.

Remove the Soxhlet extractor (if there is still a small amount of extract in the extraction cylinder, tilt it to flow all into the round bottom flask), install a condenser to distill, and when there are about 5 ml remaining, pour it into an evaporating dish containing quicklime and stir. After it becomes a paste, it is evaporated to dryness into powder, and then the crystal is obtained by sublimation.