{
  "url": "https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-8b./paragraph-2n14",
  "json_url": "https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-8b./paragraph-2n14.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/8b./paragraph/2n14",
  "kind": "paragraph",
  "number": "2",
  "heading": "Remarks",
  "text": "The titration may also be carried out using an indicator (4.26), although the change of colour is more difficult to observe.\nBlank test\n7.6.2 See 7.2.3.\nExpression of result\n7.6.3 %N(ureic)=(a-A)×0.14M where:\na = ml of standard solution of sodium or potassium hydroxide (0.1 M) (4.17) used for the blank, carried out in exactly the same conditions as the analysis.\nA = ml of standard solution of sodium or potassium hydroxide (0.1 M) (4.17) used for the analysis.\nM = mass of the sample, in grams, present in the aliquot part taken for analysis.\nGravimetric method using xanthydrol\n7.6.4 Transfer by pipette into a 100 ml beaker an aliquot portion of the filtrate (7.1) containing not more than 20 mg urea. Add 40 ml acetic acid (4.11). Stir with a glass rod for one minute. Allow any precipitate to settle for five minutes. Filter, wash with a few ml acetic acid (4.11). Add 10 ml xanthydrol solution (4.23) to the filtrate drop by drop, stirring continuously with a glass rod. Allow to stand until the precipitate appears, then stir again for one or two minutes. Allow to stand for one and a half hours. Filter, using a slight reduction in pressure, through a sintered glass crucible (5.6) which has been previously dried and weighed. Wash three times with 5 ml ethanol (4.28), without trying to remove all the acetic acid. Place in an oven at a temperature of 130°C for one hour (do not exceed 145°C). Allow to cool in a desiccator and weigh.\nExpression of result\n7.6.5 %N(ureic)6.67×mM where:\nm = mass of the precipitate in grams.\nM = mass of the sample, in grams, present in the aliquot part taken for analysis.\nCorrect for the blank.\nAlthough biuret will also be precipitated by xanthydrol, this should not give rise to a significant error in the determination since its level is generally low in absolute value in compound fertilisers.\nNote:\nAlthough biuret will also be precipitated by xanthydrol, this should not give rise to a significant error in the determination since its level is generally low in absolute value in compound fertilisers.\nDifference method\n7.6.6 Ureic N can also be calculated as indicated in the following table:\nCase\nNitric N\nAmmoniacal N\nUreic N\n1\nAbsent\nPresent\n(7.2.4)-(7.5.3)\n2\nPresent\nPresent\n(7.3.3)-(7.5.3)",
  "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/8b./paragraph/2n14",
    "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."
}