{
  "url": "https://openlegislation.uk/preservatives-in-food-regulations-1989/schedule-5/part-III/paragraph-3",
  "json_url": "https://openlegislation.uk/preservatives-in-food-regulations-1989/schedule-5/part-III/paragraph-3.json",
  "legislation": "uksi/1989/533",
  "legislation_title": "The Preservatives in Food Regulations 1989",
  "legislation_url": "https://openlegislation.uk/preservatives-in-food-regulations-1989",
  "path": "schedule/5/part/III/paragraph/3",
  "kind": "paragraph",
  "number": "3",
  "heading": "Reagents",
  "text": "The following reagents shall be used–\n(a) 70 per centum (weight/weight) orthophosphoric acid;\n(b) silicone-based anti-foaming emulsion;\n(c) di-isopentyl ether (analytical reagent grade);\n(d) purified cyclohexane: shake 3 times with a 4 per cent (weight/volume) solution of sodium hydroxide, wash 3 times with distilled water;\n(e) 4 per centum (weight/volume) sodium hydroxide solution;\n(f) buffer solution at pH 10.4: into a 2 litre graduated flask put 6.64 g. of boric acid, 8.00 g. of potassium chloride and 93.1 ml. of N sodium hydroxide solution; mix and bring up to calibration mark with distilled water;\n(g) reagent I: dissolve 1.0 g. of 4-aminophenazone (4-amino-2, 3-dimethyl-1-phenyl-5-pyrazolone; 4-aminoantipyrin) in 100 ml. of distilled water;\n(h) reagent II: dissolve 2.0 g. of potassium ferricyanide in 100 ml. of distilled water. Reagents I and II must be kept in brown glass flasks and are only stable for approximately 14 days;\n(j) silica gel;\n(k) standard solution: dissolve 10 mg. of pure 2-hydroxybiphenyl in 1 ml. of 0.1 N NaOH; dilute to 100 ml. with a 0.2 M sodium borate solution (1 ml.=100 μg. 2-hydroxybiphenyl). For the standard curve, dilute 1 ml. to 10 ml. with the buffer solution.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1989/533/schedule/5/part/III/paragraph/3",
    "retrieved_at": "2026-10-29T15:46:33.935266+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."
}