# The Preservatives in Food Regulations 1989, Paragraph 2: Principle


An extract is prepared from the peel using dichloromethane in an acid medium. The extract is concentrated and separated by thin layer chromatography using silica gel. The presence of biphenyl, 2-hydroxybiphenyl or sodium biphenyl-2-yl oxide is shown by fluorescence and colour tests.

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Source: https://www.legislation.gov.uk/uksi/1989/533/schedule/5/part/I/paragraph/2 (the official version)
Page: https://openlegislation.uk/preservatives-in-food-regulations-1989/schedule-5/part-I/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.