{ "url": "https://openlegislation.uk/feeding-stuffs-sampling-and-analysis-regulations-1999/schedule-2/part-5/paragraph-5", "json_url": "https://openlegislation.uk/feeding-stuffs-sampling-and-analysis-regulations-1999/schedule-2/part-5/paragraph-5.json", "legislation": "uksi/1999/1663", "legislation_title": "The Feeding Stuffs (Sampling and Analysis) Regulations 1999", "legislation_url": "https://openlegislation.uk/feeding-stuffs-sampling-and-analysis-regulations-1999", "path": "schedule/2/part/5/paragraph/5", "kind": "paragraph", "number": "5", "heading": "Procedure", "text": "Hydrolysis\n5.1 Weigh to the nearest 0.001 g, between 3 and 7 g of the prepared sample containing about 0.2 g of isobutylidenediurea into a concical flask (4.1). Add 100 ml buffer solution (3.4) and 20.0 ml toluene (3.1) to the sample and place in the flask a magnetic bar. Stopper firmly to ensure that the flask remains tightly closed during the hydrolysis.\nPlace the flask in the water bath (4.5) and stir vigorously for 20 minutes. Remove the flask and immerse in an ice-water bath for 5 minutes. Add 15 g sodium sulphate (3.2) and 5.0 ml internal standard solution (3.6) to the contents of the flask. Stopper the flask again, shake, return to the water bath (4.5) and warm for 3 minutes with stirring. Cool in the ice-water bath for 5 minutes. Transfer slowly between 15 and 25 ml of the mixture to the centrifuge tube (4.2), stopper, and centrifuge for 5 minutes to separate the layers. (Repeat the transfer if insufficient toluene is decanted). Transfer a portion of the upper (toluene) layer to a test tube with a pasteur pipette.\nDetermination\n5.2 Inject between 0.5 and 1.0 μl of the toluene solution (5.1) into the gas chromatograph (4.3).\nSuggested conditions:\nColumn\n70iC\nNitrogen\n40 ml per minute\nInjection\n150iC\nHydrogen\n30 ml per minute\nDetector\n150iC\nAir\n370 ml per minute\nApproximate retention times:\nIsobutyraldehyde\n1 min.\nInternal standard\n1.5 min.\nToluene\n3 min.\nMeasure the peak heights of the isobutyraldehyde and internal standard. Calculate the peak height ratio, isobutyraldehyde/internal standard, and from this value determine the quantity of isobutylidenediurea present by reference to the calibration curve (5.3).\nCalibration curve\n5.3 Weigh to the nearest mg, 100, 200 and 300 mg isobutylidenediurea (3.5) into three conical flasks (4.1). Add 100 ml buffer solution (3.3), 20.0 ml toluene (3.1) and a magnetic bar to each. Stopper the flasks firmly. Continue as in 5.1 from “… Place the flask in the water bath …”. Inject the toluene solutions into the gas chromatograph (4.3), and measure the peak heights. Calculate the peak height ratios, isobutyraldehyde/internal standard, and plot the calibration curve using peak height ratios as the ordinates and the corresponding weights or isobutylidenediurea as the abseissae.", "extent": null, "status": null, "version": "current", "annotations": [], "outstanding_effects": [ { "type": "words substituted", "affecting": "wsi/2003/1850", "affecting_title": "The Feeding Stuffs, the Feeding Stuffs (Sampling and Analysis) and the Feeding Stuffs (Enforcement) (Amendment) (Wales) Regulations 2003" }, { "type": "modified", "affecting": "wsi/2001/343", "affecting_title": "The Feeding Stuffs (Wales) Regulations 2001" }, { "type": "modified", "affecting": "wsi/2001/343", "affecting_title": "The Feeding Stuffs (Wales) Regulations 2001" }, { "type": "words added", "affecting": "uksi/2001/541", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (England) Regulations 2001" }, { "type": "words substituted", "affecting": "uksi/2001/541", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (England) Regulations 2001" }, { "type": "words added", "affecting": "uksi/2001/541", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (England) Regulations 2001" }, { "type": "words added", "affecting": "wsi/2001/2253", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (Wales) Regulations 2001" }, { "type": "words substituted", "affecting": "wsi/2001/2253", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (Wales) Regulations 2001" }, { "type": "words added", "affecting": "wsi/2001/2253", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) (Amendment) (Wales) Regulations 2001" }, { "type": "words added", "affecting": "ssi/2001/104", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) Amendment (Scotland) Regulations 2001" }, { "type": "words substituted", "affecting": "ssi/2001/104", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) Amendment (Scotland) Regulations 2001" }, { "type": "words added", "affecting": "ssi/2001/104", "affecting_title": "The Feeding Stuffs (Sampling and Analysis) Amendment (Scotland) Regulations 2001" }, { "type": "words inserted", "affecting": "uksi/2003/1296", "affecting_title": "The Feeding Stuffs (Sampling and Analysis), the Feeding Stuffs (Enforcement) and the Feeding Stuffs (Establishments and Intermediaries) (Amendment) (England) Regulations 2003" }, { "type": "applied", "affecting": "uksi/2004/3254", "affecting_title": "The Feeding Stuffs (Safety Requirements for Feed for Food–Producing Animals) Regulations 2004" }, { "type": "am", "affecting": "uksi/2006/113", "affecting_title": "The Feeding Stuffs and the Feeding Stuffs (Sampling and Analysis) (Amendment) (England) Regulations 2006" }, { "type": "words substituted", "affecting": "wsi/2003/3119", "affecting_title": "The Feeding Stuffs, the Feeding Stuffs (Sampling and Analysis) and the Feeding Stuffs (Enforcement) (Amendment) (Wales) (No.2) Regulations 2003" }, { "type": "words inserted", "affecting": "wsi/2003/1677", "affecting_title": "The Feeding Stuffs (Sampling and Analysis), the Feeding Stuffs (Enforcement) and the Feeding Stuffs (Establishments and Intermediaries) (Amendment) (Wales) Regulations 2003" }, { "type": "words substituted", "affecting": "wsi/2004/1749", "affecting_title": "The Feeding Stuffs, the Feeding Stuffs (Sampling and Analysis) and the Feeding Stuffs (Enforcement) (Amendment) (Wales) Regulations 2004" }, { "type": "words inserted", "affecting": "wsi/2004/3091", "affecting_title": "The Feeding Stuffs, the Feeding Stuffs (Sampling and Analysis) and the Feeding Stuffs (Enforcement) (Amendment) (Wales) (No. 2) Regulations 2004" }, { "type": "applied (with modifications)", "affecting": "wsi/2005/3368", "affecting_title": "The Feed (Hygiene and Enforcement) (Wales) Regulations 2005" }, { "type": "words substituted", "affecting": "wsi/2006/116", "affecting_title": "The Feeding Stuffs (Wales) Regulations 2006" }, { "type": "words substituted", "affecting": "wsi/2006/116", "affecting_title": "The Feeding Stuffs (Wales) Regulations 2006" }, { "type": "words added", "affecting": "wsi/2006/617", "affecting_title": "The Feeding Stuffs and the Feeding Stuffs (Sampling and Analysis) (Amendment) (Wales) Regulations 2006" }, { "type": "words inserted", "affecting": "wsi/2006/617", "affecting_title": "The Feeding Stuffs and the Feeding Stuffs (Sampling and Analysis) (Amendment) (Wales) Regulations 2006" }, { "type": "words substituted", "affecting": "ssi/2002/285", "affecting_title": "The Feeding Stuffs Amendment (Scotland) Regulations 2002" }, { "type": "words inserted", "affecting": "ssi/2003/277", "affecting_title": "The Feeding Stuffs (Miscellaneous Amendments) (Scotland) Regulations 2003 (revoked)" }, { "type": "applied (with modifications)", "affecting": "ssi/2005/608", "affecting_title": "The Feed (Hygiene and Enforcement) (Scotland) Regulations 2005" }, { "type": "words substituted", "affecting": "ssi/2005/605", "affecting_title": "The Feeding Stuffs (Scotland) Regulations 2005" }, { "type": "words substituted", "affecting": "ssi/2005/605", "affecting_title": "The Feeding Stuffs (Scotland) Regulations 2005" }, { "type": "words substituted", "affecting": "ssi/2005/605", "affecting_title": "The Feeding Stuffs (Scotland) Regulations 2005" } ], "provenance": { "source": "legislation.gov.uk", "source_url": "https://www.legislation.gov.uk/uksi/1999/1663/schedule/2/part/5/paragraph/5", "retrieved_at": "2026-10-29T10:36:06.238560+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." }