Abstract
BackgroundQuantitative methods for the analysis of contaminants of emerging concern (CECs) are abundant in the scientific literature. However, there are few reports on systematic methods of identification and structural identification of transformation products. For this reason, a new method based on high-resolution mass spectrometry and differential analysis was developed in order to facilitate and accelerate the process of identification and structural elucidation of transformation products CECs. This method was applied to the study of ozonation transformation products (OTPs) of the natural hormone estrone (E1).ResultsA control compare trend experiment consisting in the comparison of a control sample to several samples having been exposed to decreasing concentrations of O3(aq) indicated that 593 peaks could be associated with OTPs. After applying various filters to remove background noise, sample contaminants and signal spikes, this data set was reduced to 16 candidate peaks. By inspection of the shape of these peaks, only two compounds OTP-276 (m/z 275.12930) and OTP-318 (m/z 317.14008) were considered as good candidates for further study. Multi-stage tandem mass spectrometry (MSn) experiments of SPE extracts of the ozonated samples of E1 and of a deuterium-labeled analogue (E1-d4) showed that OTP-276 and OTP-318 had carboxylic acid and hydroxyl functional groups, as previously reported for OTPs of other hormones. Structures for these two compounds were proposed based on their MSn spectra.ConclusionThese results indicate that the method proposed is a systematic and rapid approach to study transformation products of CECs.
Highlights
Quantitative methods for the analysis of contaminants of emerging concern (CECs) are abundant in the scientific literature
A frame corresponding to an ozonation transformation products (OTPs) should not be observed in the sample E1:O3 1:0 but since some low carryover was observed between samples, residual ultra trace amounts were often detected in all the samples
Lower retention times than the parent compound are consistent with OTPs which by the addition of O and loss of C atoms tend to be more hydrophilic than the parent compound and less retained in reversed-phase columns
Summary
Quantitative methods for the analysis of contaminants of emerging concern (CECs) are abundant in the scientific literature. Conservation of biological activity after transformation is plausible if the pharmacophore of the parent compound is preserved [6] and resistance to biodegradation can result after the formation of new functional groups capable For these reasons, researchers have started to investigate the formation of TPs and have proposed molecular structures based on mass spectrometry [9], especially TPs formed after ozonation [10] which is one of the most studied tertiary water treatments. Benner and Ternes [16] based the structural elucidation of the OTPs of propranolol on product ion fragmentation trees generated by LC coupled to multi-stage tandem mass spectrometry (MSn) In spite of these studies, there are still few publications in relation to the development of systematic methods of identification and structural elucidation of TPs. Kern, et al [17] used a database to screen 1794 possible TPs of 52 organic contaminants in preconcentrated extracts of surface waters analyzed by high-resolution mass spectrometry (HRMS). Their approach was successful to identify eight TPs of organic contaminants in effluent wastewater samples
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
