Tylosin detection in animal feed by liquid chromatography-tandem mass spectrometry with enzymatic hydrolysis of the tylosin urea adduct.
When the use of tylosin as a feed additive was forbidden by Council Regulation 2821/98, the necessity of a chemical confirmation method for the monitoring of the ban was created. Recently a method was developed for the detection of tylosin in animal feed by means of LC-MS/MS. During the validation high deviating values for the decision limit, detection capability, and repeatability for tylosin in cattle feed were observed, and the presence of urea and the formation of a tylosin urea adduct (TUA) were suggested as possible explanations. In this study two hydrolysis approaches for the TUA adduct were compared, namely, a chemical hydrolysis and an enzymatic hydrolysis with urease. The latter yielded a more complete hydrolysis of urea and was used for further validation. The recovery increased by approximately 15-25% depending on the amount of urea present in the feed (0.5-2%). The decision limit and detection capability were hardly influenced by the enzymatic hydrolysis.
Van Poucke
Christof
C
Laboratory of Food Analysis, Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium. christof.vanpoucke@UGent.be
Dumoulin
Fréderic
F
De Keyser
Kirsten
K
Elliott
Chris
C
Van Peteghem
Carlos
C
D000821:Animal Feed / Q000032:analysis*; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002853:Chromatography, Liquid; D005503:Food Additives; D006868:Hydrolysis; D013058:Mass Spectrometry; D015645:Tylosin / Q000032:analysis*; D014508:Urea / Q000032:analysis*; D014510:Urease / Q000378:metabolism
D000900:Anti-Bacterial Agents; D005503:Food Additives; D014508:Urea; D014510:Urease; D015645:Tylosin