# Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis, Division 3.1.4: Purification of oil samples

Extent: E+W+S+N.I.

When necessary, the samples will be purified by passing the oil through a silica gel solid-phase extraction cartridge. A silica gel cartridge (3.1.2.8) is placed in a vacuum elution apparatus and washed with 6 ml of hexane (3.1.2.2); washing is performed without vacuum. Then a solution of the oil (0,12 g approximately) in 0,5 ml of hexane (3.1.2.2) is loaded onto the column. The solution is pulled down and then eluted with 10 ml of hexane/diethyl ether (87:13 v/v) (3.1.2.6). The combined eluates are homogenised and divided in two similar volumes. An aliquot is evaporated to dryness in a rotary evaporator under reduced pressure at room temperature. The residue is dissolved in 1 ml of heptane and the solution is ready for fatty acid analysis by GC. The second aliquot is evaporated and the residue is dissolved in 1 ml of acetone for triglyceride analysis by HPLC, if necessary.

---
Source: https://www.legislation.gov.uk/eur/1991/2568/annex/X/part/A/division/3/division/3.1/division/3.1.4 (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-X/part-A/division-3/division-3.1/division-3.1.4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.