Liquid chromatographytandem mass spectrometry methods for determination of stanozolol and l6ß-hydroxy-stanozolol in animal urine.

Introduction: Because of the activities and effects they induce, hormones are prohibited for use for anabolic purposes in farm animals intended for slaughter, which is regulated in the European Union by relevant legal provisions. Therefore, there is an obligation to monitor residues of hormones in animals and food of animal origin to ensure consumer safety. A hormone banned but used formerly for fattening cattle, stanozolol, and its metabolite 16ß-OH-stanozolol are synthetic compounds that belong to a large group of steroid hormones. This study investigates residues of these compounds in animal urine. Material and Methods: From 2006-2022, 2,995 livestock urine samples were tested for stanozolol residues in Poland as part of the National Residue Monitoring Programme. A liquid chromatography-tandem mass spectrometry method to determine stanozolol and 16ß-OH-stanozolol in animal urine was developed and validated according to the required criteria. Urine sample analysis was based on enzymatic hydrolysis of hormones potentially present in it to the free form, extraction of them from the sample with a mixture of n-hexane and butyl alcohol, purification of an extract on an NH2 amine column and finally, instrumental detection. Results: The apparent recovery and precision parameters of the developed method were in line with the established criteria, while its decision limits CCα and detection capabilities CCß were lower than the recommended concentration for analytical purposes set at 2 µg L-1 (valid until December 15, 2022; currently set as 0.5 µg L-1). Conclusion: All examined samples were compliant with the evaluation criteria.

Liquid chromatography tandem mass spectrometry with ion trap and triple quadrupole analyzers for determination of thyreostatic drugs in urine and muscle tissue.

Liquid chromatography tandem mass spectrometry methods were developed and validated to screen for and confirm residues of the thyreostatic drugs: tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil in bovine and porcine urine and muscle tissues using dimethylthiouracil as internal standard. Thyreostats were extracted from urine samples with diethyl ether after derivatisation with 3-iodobenzylbromide in basic medium (pH 8.0) and analyzed by gradient elution on a Nucleosil C18 column with ion trap mass spectrometry detection using an electrospray source and triple quadrupole MS detection with turbo spray source. Thyreostats were extracted from muscle tissue with methanol, the denaturation of matrix protein was performed and then the same steps as for the urine samples were carried out. The methods were validated in accordance with the Commission Decision 2002/657/EC. Good thyreostats recoveries were obtained (from 82% to 117%) as well as acceptable within-lab reproducibility. The values of the decision limit CCα and the detection capability CCß of five thyreostatic drugs are found to be below the recommended concentration set at 10 µg L(-1) (kg(-1)). The results of the validation demonstrate that liquid chromatography mass spectrometry with ion trap detection does not meet the criteria for confirmation for some thyreostats and therefore was applied for screening purpose only.

Residue control of coccidiostats in food of animal origin in Poland during 2007-2010.

Coccidiostats are widely used as feed additives to prevent coccidiosis. The off-label use of anticoccidials or feeding non-target animals with cross-contaminated feedingstuffs may result in the occurrence of coccidiostat residues in animal tissues and eggs. In EU countries, food of animal origin is subjected to official control of residues according to Council Directive 96/23/EC. In Poland, within the framework of the National Residue Control Plan, 3718 samples (3533 targeted and 185 suspect) of animal liver, eggs, drinking water and feed were tested for coccidiostats between 2007 and 2010. Violative residues of nicarbazin, lasalocid, maduramicin, salinomycin, semduramicin and robenidine were detected in 77 food samples (53 samples of chicken liver, 23 samples of eggs and 1 sample of turkey liver). A high percentage (31%) of non-compliant feed samples collected during follow-up investigations was observed, which confirms that feed cross-contamination may be the reason of the occurrence of coccidiostat residues in food.