http://www.legislation.gov.uk/nisr/1991/540/schedule/2/crossheading/determination-of-cyanamide-nitrogen/paragraph/4.9/madeThe Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1991Local GovernmentGovernment Printer for Northern Ireland2016-09-06AGRICULTURESCHEDULE 2METHODS OF ANALYSIS6.DETERMINATION OF CYANAMIDE NITROGENREAGENTS4.9Sodium or potassium hydroxide, 0.1 N solution.