{
  "url": "https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-25j./paragraph-7",
  "json_url": "https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-25j./paragraph-7.json",
  "legislation": "nisr/1996/513",
  "legislation_title": "Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1996",
  "legislation_url": "https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996",
  "path": "schedule/2/part/I/chapter/25j./paragraph/7",
  "kind": "paragraph",
  "number": "7",
  "heading": "PROCEDURE",
  "text": "Preparation of the blank solution\n7.1 Prepare a blank solution by repeating the whole procedure from the extraction stage, omitting only the test sample of fertiliser.\nPreparation of the series of calibration solutions\n7.2 Prepare a series of at least six calibration solutions of increasing concentration corresponding to the optimum response range of the spectrometer.\nFor the interval 0-12.5 μg molybdenum, place 0, 1, 2, 3, 4 and 5 ml, respectively, of the working solution (4.7.3) in the separating funnels (5.2). Make up to 50 ml with 6 M hydrochloric acid (4.1). The funnels contain, respectively, 0, 2.5, 5, 7.5, 10 and 12.5 mg molybdenum.\nDevelopment and separation of the complex\n7.3 To each separating funnel (6.2, 7.1 and 7.2), add in the following order:\n— 10 ml of the copper solution (4.2);\n— 20 ml of the ascorbic acid solution (4.3);\nmix thoroughly and wait for two or three minutes. Then add:\n— 10 ml of n-butyl acetate (4.4), using a precision pipette;\n— 20 ml of the thiocyanate solution (4.5).\nShake for one minute to extract the complex into the organic phase; allow to separate; after the separation of the two phases, draw off the entire aqueous phase and discard it; then wash the organic phase with:\n— 10 ml of the stannous chloride solution (4.6).\nShake for one minute. Allow to separate and draw off the entire aqueous phase. Remove the organic phase in a test tube; this will make it possible to collect the drops of water in suspension.\nDetermination\n7.4 Measure the absorbencies of the solutions obtained at 7.3 at a wavelength of 470 nm using the 0 mg/ml molybdenum calibration solution (7.2) as a reference.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/I/chapter/25j./paragraph/7",
    "retrieved_at": "2026-10-29T02:32:40.012993+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."
}