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

ABSTRACT

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. The Technical Committee (TC) 327 of the European Committee for Standardisation (CEN) commissioned the standardisation of a method for the analysis of melamine and cyanuric acid in animal feed. One main task in the standardisation process is the performance of a full international collaborative trial, which is described in this paper. After performing a pre-trial study, in the main study eight different feed samples with different concentration levels of melamine and/or cyanuric acid were distributed as double-blind samples to 13 participants. The minimum criterion of eight laboratories submitting results per sample is fulfilled for melamine but only partly for cyanuric acid. The evaluation showed for both analytes a Horwitz ratio (HorRat) well below 2, and meets the requirements stated in the appropriate international protocols. The results demonstrated that the method seems to be suitable for the analysis of melamine and cyanuric acid in animal feed.

KEYWORDS:

• Melamine
• cyanuric acid
• standardisation
• CEN
• animal feed
• collaborative trial

Acknowledgments

The authors thank the participants of the collaborative trial for their cooperation and valuable comments used to optimise the method, the CEN/TC 327/WG1: Animal Feedingstuffs, “Organic contaminants” for scientific input and the European Commission for funding this study.

Disclosure statement

No potential conflict of interest was reported by the authors.