Determination of the Thyreostats in Animal Feeding Stuffs Using Liquid Chromatography-Tandem Mass Spectrometry

Abstract

A rapid liquid chromatography tandem mass spectrometry method was developed and validated to detect and confirm five thyreostatic drugs: tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil in animal feeding stuff samples. Thyreostats were extracted from feed with methanol, and then degreasing of the extract with petroleum ether was performed, followed by the derivatisation of the compounds with 3-iodobenzylbromide in basic medium (pH 8.0). The derivatives were extracted with diethyl ether and analysed by gradient elution on a Poroshell 120-EC C18 column with triple quadrupole MS detection with turbo spray source in positive ionisation mode. The method was validated in accordance with the Commission Decision 2002/657/EC. For validation level of 10 μg kg -1 , the recovery ranged from 82% to 97.5% for all examined compounds. The repeatability and reproducibility did not exceed the limit of 20% for all analytes. The linearity was good for all thyreostats in the whole range of tested concentrations, as proved by the correlation coefficients greater than 0.99. The decision limits (CC) ranged from 1.63 μg kg -1 to 3.95 μg kg -1 , whereas the detection capabilities (CC) ranged from 2.74 μg kg -1 to 6.73 μg kg -1 . The developed analysis is sensitive and robust, and therefore useful for quantification and confirmation of thyreostats in residue control programme.

Analysis of thyreostats in bovine feces using ultra high performance liquid chromatography with tandem mass spectrometry

“…Expanded uncertainty estimated for the tested compounds ranged from 26 to 46%. In other matrixes, such as milk and feeding stuff , similar values were obtained for thyreostats.…”

“…Extraction of thyreostats from matrix with solvents of different polarity such as methanol , acetonitrile , ethyl acetate , and tert ‐butyl methyl ether was carried out. Further purification of the extract involved either LLE with petroleum ether , ethyl acetate , or diethyl ether or a combination of LLE with SPE, mainly with silica cartridges , depending on the type of matrix. The application of gel permeation chromatography and QuEChERS as an alternative clean‐up strategy was also described.…”

Pojavnost tiouracila u svinjećim i goveđim urinima prikupljenih na hrvatskim farmama

“…Thiouracil or 2-thiouracil (TU) belongs to the group of thyrostats, orally active drugs that disturb the normal function of the thyroid gland by inhibiting synthesis of the thyroid hormones triidothyronine (T3) and thyroxine (T4) (Courthey et al, 2002;Vanden Bussche et al, 2011a;Woźniak et al, 2014), and by increasing water absorption and retention within edible tissue and the gastrointestinal tract (Pinel et al, 2006a). Thyrostats are usually easy to use, they are active per os and effective after administration with feed (Woźniak et al, 2018).…”

“…However, the possible presence of thyrostat residues in meat and other products derived from treated animals pose a threat to human health (Pinel et al, 2006a(Pinel et al, , 2006bWoźniak et al, 2014;Samardžija et al, 2020). The International Agency for Research on Cancer (IARC, 2001) classified these compounds in group 2B (possibly carcinogenic to humans), and they have been banned in Europe for animal fattening purposes since 1981 (EC 81/602, 1981).…”

“…Research has shown that the presence of TU in urine can be the result of abuse, but also of a diet rich in cruciferous plants (Brassicaceae) (Woźniak et al, 2014). Pinel et al (2006b) proved that there is a link between genus Brassicaceae feeding and detected TU in urine animals, though these concentrations do not exceed 10 μg/L.…”