Interlaboratory validation of an LC-MS/MS method for the determination of melamine and cyanuric acid in animal feed.

Melamine and cyanuric acid have been mixed illegally into food and feed to increase the nitrogen content, which results in deceptively high protein contents. As a consequence, a maximum level for melamine of 2.5 mg kg-1 feed was established by the European Union under Directive 2002/32/EC.