Residue study of nitroimidazoles depletion in chicken feathers in comparison with some other selected matrixes.

This paper presents the results from a residue study conducted on a statistically representative number of chicken broilers that were individually orally treated with the selected nitroimidazoles (metronidazole, ornidazole and ipronidazole) in an appropriate amount close to the theoretical therapeutic dose. A mutual persistence comparison of the monitored analytes in feathers, serum, muscle and shanks was performed and attention was also paid to selected metabolites (hydroxymetronidazole and hydroxyipronidazole). An analytical LC/MS/MS method using SupelMIP SPE nitroimidazoles cartridges was developed for the determination of nitroimidazoles residues in poultry feathers, serum, muscle and shanks and the method was validated according to Commission Decision 2002/657/EC.

Method for the determination of thyreostats in milk samples using LC-MS/MS.

A sensitive and selective analytical method for the determination of four thyreostats (tapazol, thiouracil, methylthiouracil and propylthiouracil) in cow's milk, lamb's milk, and goat's milk was developed and validated according to 2002/657/EC criteria. Proteins in milk samples were precipitated by acetonitrile and analytes were derivatised with 3-iodobenzylbromide. Afterwards, derivatives were separated from the matrix by liquid-liquid extraction with ethyl acetate as an organic solvent and analysis was carried out using LC-MS/MS in a positive electrospray mode.