BS EN ISO 734-2:2010 pdf download.Oilseed meals – Determination of oil content Part 2: Rapid extraction method (ISO 734- 2:2008, corrected version 2009-06-01).
Use only reagents of recognized analytical grade, unless otherwise specified.
5.1 Technical hexane, n-hexane or light petroleum ether, essentially composed of hydrocarbons with six carbon atoms, of which less than 5 % distils below 50 °C and more than 95 % distils between 50 °C and 70 °C.
For either solvent, the residue on complete evaporation shall not exceed 2 mg per 100 ml.
The solvent recovered from the extract by distillation should not be used for further determinations.
5.2 Cotton wool, fat-free.
EXAMPLE Defatted cotton wool for ophthalmic use.
6 Apparatus
Usual laboratory apparatus and, in particular, the following.
6.1 Analytical balance, capable of being read to the nearest 0,001 g.
6.2 Drying oven, capable of being maintained at 103 °C ± 2 °C.
6.3 Mechanical microgrinder, capable of wet grinding in the presence of light petroleum ether and reducing the test portion to an average particle size of less than 10 pm. A commercially available ball mill1) is suitable.
When using grinding beakers made of polytetrafluoroethylene, cooling is obligatory. A suitable cooling jacket is shown in Figure 1.
6.4 Funnel, made of light petroleum ether-resistant plastic, with a diameter of 70 mm, a stem external diameter of 10 mm and a stem length of 100 mm to 150 mm.
The stem shall just reach into the extraction thimble on placing the funnel in the extraction apparatus as described in 9.3.4. There is a fixed metal pin in the funnel to retain the stainless steel balls (see Figure 2).
6.5 Continuous extraction apparatus 2), with ground joints, consisting of a flat bottomed flask of capacity 100 ml to 200 ml, a connecting tube (extractor) to hold the extraction thimble, and a reflux condenser. The apparatus should include a suitable heating element for boiling technical hexane under reflux conditions. This might be a water bath, steam bath or safety-approved electrical heating unit.
NOTE The use of other extractors is conditional upon the results of a test on a standard material of known oil content to confirm the suitability of the apparatus.
6.6 Extraction thimbles, of dimensions 25 mm x 100 mm, of wall thickness 1,5 mm and a reinforced bottom part.
7 Sampling
A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage.
Sampling is not part of the method specified in this part of ISO 734. A recommended sampling method is given in ISO 5500111.
8 Preparation of test sample
Prepare the test sample in accordance with ISO 5502.
9 Procedure
9.1 General
If it is required to check whether the repeatability limit (11.2) is met, carry out two single determinations in
accordance with 9.2109.3.11.
9.2 Test portion
Weigh, to the nearest 0,001 g, 5 g of the well-mixed test sample in an extraction thimble (6.6).
9.3 Determination
9.3.1 Transfer the contents of the thimble to the beaker or tube of the mechanical microgrinder (6.3) containing all stainless-steels balls.
9.3.2 Add about 20 ml of solvent (5.1). Close the grinding beaker or tube and shake in the microgrinder (6.3) for 10 mm or shake the stainless steel tubes horizontally on a flat bed shaker for 45 mm horizontally at a frequency of 240 min1, with a horizontal displacement of 35 mm.
9.3.3 Place the thimble (6.6) in the connecting tube (extractor) of the extraction apparatus (6.5) and connect this to a dried and weighed flask.
9.3.4 Place the funnel (6.4) in the connecting tube in such a manner that the stem of the funnel reaches into the upper quarter of the thimble.
9.3.5 Then pour the contents of the grinding beaker through the funnel into the extraction thimble in such a manner that the balls remain on the metal pin in the funnel. Carefully rinse the grinding beaker, its lid and the balls with solvent in order to transfer all sample particles quantitatively into the extraction thimble. This requires about 50 ml of solvent, the total volume of which is therefore about 70 ml.
9.3.6 Cover the contents of the extraction thimble with a wad of cotton wool (5.2). Connect the flask and connecting tube (extractor) to the condenser and place the whole apparatus on the heating apparatus.
9.3.7 Extract for 1 h, calculated from when the solvent begins to boil, while maintaining a reflux rate of at least 5 mI/mm.
9.3.8 Collect the bulk of the solvent in the collecting vessel of the extraction apparatus using the appropriate actions. Discard recovered solvent.
9.3.9 Remove the flask from the extraction apparatus and leave for about 5 mm on the boiling water bath to evaporate any residual solvent.BS EN ISO 734-2 pdf download.