{
  "url": "https://openlegislation.uk/eu-directive-1979-796/annex-II/division-7/division-6/division-6.1",
  "json_url": "https://openlegislation.uk/eu-directive-1979-796/annex-II/division-7/division-6/division-6.1.json",
  "legislation": "eudr/1979/796",
  "legislation_title": "First Commission Directive of 26 July 1979 laying down Community methods of analysis for testing certain sugars intended for human consumption (79/796/EEC)",
  "legislation_url": "https://openlegislation.uk/eu-directive-1979-796",
  "path": "annex/II/division/7/division/6/division/6.1",
  "kind": "division",
  "number": "6.1",
  "heading": "Standardization of the Luff-Schoorl reagent (4.3)",
  "text": "6.1.1. To 25 ml of Luff-Schoorl reagent (4.3) add 3 g of potassium iodide and 25 ml of 3 mol/litre sulphuric acid (4.6).\nTitrate with 0·1 mol/litre sodium thiosulphate (4.4) using starch solution (4.5) as indicator added towards the end of the titration. If the volume of 0·1 mol/litre sodium thiosulphate used is not 25 ml the reagent must be made up afresh.\n6.1.2. Pipette 10 ml of the reagent into a 100 ml volumetric flask and dilute to volume with water.\nPipette 10 ml of the diluted reagent into 25 ml of 0·1 mol/litre hydrochloric acid (4.11) in a conical flask and heat for one hour in a boiling water-bath. Cool, make up to the original volume with freshly boiled water and titrate with 0·1 mol/litre sodium hydroxide (4.10) using phenolphthalein (4.12) as indicator.\nThe volume of 0·1 mol/litre sodium hydroxide (4.10) used must be between 5·5 and 6·5 ml.\n6.1.3. Titrate 10 ml of the diluted reagent (6.1.2) with 0·1 mol/litre hydrochloric acid (4.11) using phenolphthalein (4.12) as indicator. The end-point is characterized by the disappearance of the violet colour.\nThe volume of 0·1 mol/litre hydrochloric acid (4.11) used must be between 6·0 and 7·5 ml.\n6.1.4. The pH of the Luff-Schoorl reagent must be between 9·3 and 9·4 at 20 oC.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eudr/1979/796/annex/II/division/7/division/6/division/6.1",
    "retrieved_at": "2026-11-01T15:23:41.440766+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."
}