Background: Quantitative 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).
Results: A 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.
Conclusion: These results indicate that the method proposed is a systematic and rapid approach to study transformation products of CECs.
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http://dx.doi.org/10.1186/1752-153X-7-74 | DOI Listing |
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The Petroleum and Petrochemical College, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
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The present study examined the corrosion protection of aluminium in 1M HCl by deploying expired danacid, with techniques such as gravimetric, electrochemical, and density functional theory (DFT). Inhibitor characterization was executed with Fourier transform infrared (FTIR) spectroscopy and gas chromatography mass spectrometry (GC-MS), which was supplemented by optimization of parameters with response surface methodology. The results of gravimetric study indicates that the inhibition efficiency (IE) rose with rise in danacid concentration and reduced with rise in temperature.
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