{
  "url": "https://openlegislation.uk/eu-regulation-1991-2568/annex-IV/division-5/division-5.1",
  "json_url": "https://openlegislation.uk/eu-regulation-1991-2568/annex-IV/division-5/division-5.1.json",
  "legislation": "eur/1991/2568",
  "legislation_title": "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",
  "legislation_url": "https://openlegislation.uk/eu-regulation-1991-2568",
  "path": "annex/IV/division/5/division/5.1",
  "kind": "division",
  "number": "5.1",
  "heading": "Preparation of the chromatographic column.",
  "text": "Suspend 15 g of silica gel (4.1) in the n-hexane (4.2) and introduce it into the column (3.2). Allow to settle spontaneously. Complete settling with the aid of an electrovibrator (3.5) to make the chromatographic layer more homogeneous. Percolate 30 ml of n-hexane to remove any impurities. Using the balance (3.8) weigh exactly 500 mg of the sample into the 25 ml Erlenmeyer flask (3.1), add the appropriate quantity of the internal standard (4.5) according to the presumed wax content. For example, add 0,1 mg of lauryl arachidate for olive oil, and 0,25 to 0,5 mg for olive-residue oil. Transfer the prepared sample to the chromotography column using two 2 ml portions of n-hexane (4.2).\nAllow the solvent to flow away until it reaches 1 mm above the upper level of the absorbant then percolate a further 70 ml of n-hexane in order to eliminate the n-alkanes naturally present. Then start the chromatographic elution by collecting 180 ml of the mixture of n-hexane/ethyl ether (ratio 99:1), keeping a rate of flow of approximately 15 drops every 10 seconds. Elution of the sample must be carried out at a room temperature of 22 ± 4 °C.\nDry the fraction thus obtained in a rotary evaporator (3.6.) until virtually all the solvent has been eliminated. Eliminate the final 2 ml of solvent with the aid of a weak current of nitrogen; then add 2-4 ml n-heptane.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Substituted by Commission Regulation (EC) No 702/2007 of 21 June 2007 amending Commission Regulation (EEC) No 2568/91 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/1991/2568/annex/IV/division/5/division/5.1",
    "retrieved_at": "2026-11-01T15:01:50.986318+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}