New method for the rapid identification of tetracycline residues in foods of animal origin - using the PremiTest in combination with a metal ion chelation assay. 
A post-screening classification assay for tetracycline compounds has been developed and integrated into the previously reported optimized PremiTest methodology.  The new post-antimicrobial screening assay is based on a metal ion chelation using calcium and sodium chloride and has been shown to be specific towards the tetracycline class.  The assay is both cost-effective and complementary to the post-screening procedures that have previously been developed for the beta-lactam and sulfonamide compounds.  A validation study was conducted in accordance with 2002/657/EC (Commission Decision).  The method is rugged and applicable to a range of tetracyclines of differing antimicrobial potencies over a wide concentration range.  A blind trial was undertaken in which all antimicrobial residues in the unknown samples were successfully identified by the analyst following the integrated PremiTest procedure for the classification of antimicrobial compounds.