Ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry detection of naturally occurring thiouracil in urine of untreated livestock, domesticated animals and humans

• Published in: Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment Vol. 28; no. 2; pp. 166 - 172
• Main Authors: Vanden Bussche, J, Vanhaecke, L, Deceuninck, Y, Wille, K, Bekaert, K, Le Bizec, B, De Brabander, H.F
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.02.2011; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Adult; animal feed; animal feedingstuffs; animal production; Animals; Animals, Domestic; Biological and medical sciences; Brassicaceae; Chromatography; Chromatography, High Pressure Liquid; clean-up; Correlation analysis; Cross-Over Studies; derivatization; Diet; drug residues; European Union; exposure; extraction; Female; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; hormones; human population; Human subjects; Humans; Limit of Detection; liquid chromatography/mass spectrometry; Livestock; Male; Mass spectrometry; Methods of analysis, processing and quality control, regulation, standards; processed foods; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; thiouracil; Thiouracil - chemistry; Thiouracil - urine; ultra-performance liquid chromatography; Urine; Vegetables; European Union; Human; Hormone; Drug; Urine; animal feed; Biological fluid; hormones; clean-up; liquid chromatography/mass spectrometry; HPLC chromatography; Liquid chromatography; vegetables; processed foods; drug residues; Analysis method; exposure; Residue; Animal; Extraction; Control method; Detection; Mass spectrometry; animal feedingstuffs
• ISSN: 1944-0057; 1944-0049; 1944-0057
• DOI: 10.1080/19440049.2010.544681

Thiouracil belongs to the xenobiotic thyreostats, which are growth-promoting agents illegally used in animal production. Recently it has been reported that thiouracil is suspected to have a natural origin. The European Union of Reference Laboratory guidance paper of 2007 acknowledged this by stating that thiouracil concentrations below 10 µg l⁻¹ might have a natural origin derived from the consumption of Brassicaceae. The present research aimed at endorsing this possible natural occurrence. Urine samples of animals (livestock and domesticated) with known and unknown clinical backgrounds were analysed for thiouracil with a newly developed ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometric analysis method without derivatisation. In addition, a small-scale 9-day human experiment with Brassicaceae vegetables was performed to investigate if this natural prevalence could be extrapolated to the human population. The untreated animals had thiouracil concentrations below 10 µg l⁻¹ acknowledging the alleged natural occurrence of thiouracil. As for the humans, in 66.7% of the urine samples thiouracil was found above the CCα of 2.2 µg l⁻¹. However, the correlation with the Brassicaceae diet proved to be non-significant (p = 0.095). Nevertheless, these results clearly demonstrate the natural occurrence of thiouracil in urine of animals and humans. The exact origin of this natural thiouracil trace still needs to be identified.