Development and validation of an optical SPR biosensor. Assay for tylosin residues in honey

In recent years there has been an increase in the use of tylosin in apiculture as bacterial brood diseases become resistant to oxytetracycline. Confirmatory mass spectrometry based methods have been developed but up until now there has been no complementary screening method available capable of sub 10 mu g kg(-1) detection limits. In this paper the development and validation of a screening method using optical biosensor technology is presented. The honey was first dissolved in a phosphate buffer and following solid-phase extraction (SPE) cleanup was analyzed using a Biacore Q instrument. Using the criteria specified in European Commission Decision 2002/657/EC for qualitative screening methods, the detection capability (CC beta) of the method was determined to be 2.5 mu g kg(-1). Honey samples containing trace residue levels of tylosin were analyzed by both the biosensor screening method and a LC-MS/MS confirmatory procedure; the results were in good agreement.