Investigation of the presence of endogenous prednisolone in equine urine by high-performance liquid chromatography mass spectrometry and high-resolution mass spectrometry
Articolo
Data di Pubblicazione:
2012
Citazione:
Investigation of the presence of endogenous prednisolone in equine urine by high-performance liquid chromatography mass spectrometry and high-resolution mass spectrometry / M. Fidani, G. Pompa, F. Mungiguerra, A. Casati, M.L. Fracchiolla, F. Arioli. - In: RAPID COMMUNICATIONS IN MASS SPECTROMETRY. - ISSN 0951-4198. - 26:8(2012), pp. 879-886.
Abstract:
RATIONALE: After the detection of low concentrations of prednisolone in racehorse urine samples collected at Italian
racetracks, a study was initiated to investigate the accuracy of the analytical protocol used and the possible endogenous
origin of detected prednisolone.
METHODS: Multiple reaction monitoring (MRM) MS2 acquisition with a triple quadrupole (n = 780) and full scan MS2
and MS3 (n = 180) acquisition with a linear ion trap were checked. As a further confirmation, ten urine samples were
analysed by high-resolution mass spectrometry (HRMS).
RESULTS: The study showed the difficulty of identifying prednisolone, probably due to interfering compounds with the
same molecular weight (360 Da) present in the matrix. The characteristic transitions for prednisolone were identified,
both in MS2 and MS3, as the ions 187 and 280; the ion 295 was also used for identification. The concentrations detected
with the triple quadrupole and the linear ion trap were not statistically different. The exact mass of prednisolone formiate
(the adduct acting as a molecular ion) was identified by HRMS.
CONCLUSIONS: The very high frequency of prednisolone detection in the samples (78.5%), the low concentration of this
steroid and, importantly, the narrow range of the 95% confidence limits (0.97–1.05 in MS2 mode and 0.88–1.04 in MS3
mode), could represent evidence that its presence is endogenous. In the light of these results, this hypothesis seems the
most probable, even if further studies are required to confirm it. Furthermore, a microbiological origin (i.e. fermentation
of cortisol after sample collection) could not be disregarded.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
horse urine; prednisolone; endogenous
Elenco autori:
M. Fidani, G. Pompa, F. Mungiguerra, A. Casati, M.L. Fracchiolla, F. Arioli
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