Identification of the unknown transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high-resolution mass spectrometry
Article first published online: 22 JUN 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 26, Issue 15, pages 1687–1704, 15 August 2012
How to Cite
Calza, P., Medana, C., Padovano, E., Giancotti, V. and Baiocchi, C. (2012), Identification of the unknown transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high-resolution mass spectrometry. Rapid Commun. Mass Spectrom., 26: 1687–1704. doi: 10.1002/rcm.6279
- Issue published online: 22 JUN 2012
- Article first published online: 22 JUN 2012
- Manuscript Accepted: 16 MAY 2012
- Manuscript Revised: 14 MAY 2012
- Manuscript Received: 4 APR 2012
A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high-resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study.
The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ-Orbitrap analyzer. High-resolution mass spectrometry was employed to assess the evolution of the drug transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different transformation products (TPs) and to distinguish the isobaric species.
The simulation of phototransformation occurring in the aquatic environment and identification of biotic and abiotic transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty-eight main species were identified after carbamazepine transformation and twenty-nine for clarithromycin.
This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the transformation pathways followed by the two drugs. Copyright © 2012 John Wiley & Sons, Ltd.