Limits...
Identification and structural elucidation of ozonation transformation products of estrone.

Segura PA, Kaplan P, Yargeau V - Chem Cent J (2013)

Bottom Line: 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.Structures for these two compounds were proposed based on their MSn spectra.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemical Engineering, McGill University, 3610 University, Montreal, QC, H3A 2B2, Canada. viviane.yargeau@mcgill.ca.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Fragmentation tree of OTP-318 showing the most probable elemental composition of the main MSn product ions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3643888&req=5

Figure 3: Fragmentation tree of OTP-318 showing the most probable elemental composition of the main MSn product ions.

Mentions: In summary, MSn experiments with the ozonated extracts of E1 and E1-d4 showed that a carboxylic acid and a hydroxyl group are present in the OTP-318 molecule. The other fragments showed in Figure 3 did not indicate unambiguously the presence of other functional groups in the molecular structure of OTP-318. Similarly to the fragments observed during the MSn experiments performed with OTP-276, the elemental composition of the MS3 and MS4 product ions of OTP-318 pointed towards a partial preservation of the ring structure of E1. However, typical negative even-electron losses such as H2 and CH4 were observed less frequently than in OTP-276, probably due to the presence of 2 more O atoms in the structure OTP-318 parent ion which could have an impact on the possible fragmentation mechanisms. The proposed structures in Figure 1 (OTP-318A and OTP-318B) also hint that at least 4 configuration isomers are probable for this molecule given the presence of two carbon double bonds in its structure. This could explain the observation of at least three peaks at m/z 317.14 ± 0.01 in the chromatogram of the SPE extracts of the ozonated E1 solutions (Additional file 1: Figure S1).


Identification and structural elucidation of ozonation transformation products of estrone.

Segura PA, Kaplan P, Yargeau V - Chem Cent J (2013)

Fragmentation tree of OTP-318 showing the most probable elemental composition of the main MSn product ions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643888&req=5

Figure 3: Fragmentation tree of OTP-318 showing the most probable elemental composition of the main MSn product ions.
Mentions: In summary, MSn experiments with the ozonated extracts of E1 and E1-d4 showed that a carboxylic acid and a hydroxyl group are present in the OTP-318 molecule. The other fragments showed in Figure 3 did not indicate unambiguously the presence of other functional groups in the molecular structure of OTP-318. Similarly to the fragments observed during the MSn experiments performed with OTP-276, the elemental composition of the MS3 and MS4 product ions of OTP-318 pointed towards a partial preservation of the ring structure of E1. However, typical negative even-electron losses such as H2 and CH4 were observed less frequently than in OTP-276, probably due to the presence of 2 more O atoms in the structure OTP-318 parent ion which could have an impact on the possible fragmentation mechanisms. The proposed structures in Figure 1 (OTP-318A and OTP-318B) also hint that at least 4 configuration isomers are probable for this molecule given the presence of two carbon double bonds in its structure. This could explain the observation of at least three peaks at m/z 317.14 ± 0.01 in the chromatogram of the SPE extracts of the ozonated E1 solutions (Additional file 1: Figure S1).

Bottom Line: 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.Structures for these two compounds were proposed based on their MSn spectra.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemical Engineering, McGill University, 3610 University, Montreal, QC, H3A 2B2, Canada. viviane.yargeau@mcgill.ca.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus