SPE–UPLC–MS/MS for Determination of 36 Monomers of Alkylphenol Ethoxylates in Tea
, Li Zhou * and Fengjian Luo *
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn its current form, the manuscript can be accepted.
Author Response
Dear reviewer,
Thank you very much for your review of our manuscript entitlied “Analysis of Alkylphenol Ethoxylates in Tea by SPE Coupled to UPLC-MS/MS” (Manuscript ID: 2281710).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript “Analysis of Alkylphenol Ethoxylates in Tea by SPE Coupled to UPLC-MS/MS” by Lin Qin, Qin Yujie, Sun Hezhi, Wang Xinru, Yang Mei, Zhang Xinzhong, Zhou Li, Luo Fengjian describes the optimization of some parameters of the method for determination of alkylphenol ethoxylates in tea samples using UPLC-MS/MS. I think that due to their toxic properties, the determination of these compounds in various types of teas is advisable. Therefore, a rapid method for their determination is needed.
I have some comments which could influence on the value of the manuscript and can improve their quality:
1. Is Germany not part of the European Union? Line 48 page 2.
2. Not all tables and figures need to be included in the main manuscript. Some can be moved to supplementary material (for example table 1 and table 2 or figure 1, 2 and 8).
3. Figure 3 is unreadable, maybe from all figures make two for example: a) OPEO, b) NPEO.
4. Whether spaces are needed after the colon? line18-23 page 5
5. Shouldn't the stoichiometric indices in the formulas be in subscript? Figure 5 and 6
6. Was the validation of the method carried out according to some guide? If yes, with what document. If not, what are the acceptable validation parameters and from where they were taken?
7. The results and discussion include some elements of comparison with another methods, but not enough. Authors should describe advantages of the method compared to other reported methods. Can prepare a table with a short description of methods optimized by other researchers.
8. I think that figure 8 „Concentration of…” should be figure 9. Please, change the numer of figure in the text and under the figure.
9. Different types of tea were studied, so the following question arises: was there any correlation noted for the occurrence of any of the tested compounds in a particular type of tea? (section 2.4)
10. What type of tea was used for validation and why?
11. I know that the authors plan to assessment of dietary intake in the future. However, my question is why not do it in this work. It would increase the value of this work.
12. Preparing references is not in accordance with the requirements of the journal. Titles of articles should be abbreviated and capitalized: Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.
13. Please, corrected the word „china” line 106 page 15; the abbreviation „quechers” line 71 page 17 etc. Please, check all position in references very carefully.
Author Response
Dear reviewer,
Thank you for your valuable comments concerning our manuscript entitlied “Analysis of Alkylphenol Ethoxylates in Tea by SPE Coupled to UPLC-MS/MS” (Manuscript ID: 2281710). Those comments are all helpful for revising and improving our paper. We have studied all comments carefully and have made conscientious correction. The main correction in the paper and the responds to the reviewer’s comments are as following.
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The manuscript “Analysis of Alkylphenol Ethoxylates in Tea by SPE Coupled to UPLC-MS/MS” by Lin Qin, Qin Yujie, Sun Hezhi, Wang Xinru, Yang Mei, Zhang Xinzhong, Zhou Li, Luo Fengjian describes the optimization of some parameters of the method for determination of alkylphenol ethoxylates in tea samples using UPLC-MS/MS. I think that due to their toxic properties, the determination of these compounds in various types of teas is advisable. Therefore, a rapid method for their determination is needed.
- I have some comments which could influence on the value of the manuscript and can improve their quality:
- Is Germany not part of the European Union? Line 48 page 2.
Response:
Thank you for this valuable feedback. We changed the sentence "Therefore, the use of such compounds in production has been banned or strictly monitored in Germany, Switzerland and European Union." into "Therefore, the use of such compounds in production has been banned or strictly monitored in the European Union " (Line 51, page 2)
- Not all tables and figures need to be included in the main manuscript. Some can be moved to supplementary material (for example table 1 and table 2 or figure 1, 2 and 8).
Response:
We appreciate the reviewer for this kind recommendation. We have added supplementary materials, including the following contents.
Table 1 Mass spectrometric parameters for monitoring OPEO3-20 and NPEO3-20. (Now Table S1)
Table 2 Validated parameters of APEO3-20 in spiked tea samples. (Now Table S2)
Figure 1. Full-scan mass spectra of (A) OPEO (9-10) (nEO = 3-15), (B) OPEO (16) (nEO = 9-20), (C) NPEO (4) (nEO = 9-11), (D) NPEO (9-10) (nEO = 3-15), and (E) NPEO (14) (nEO = 6-20) in 5 mg/kg standards. (Now Figure S1)
Figure 2. Chromatograms of (A) NPEO17 and NPEO19 combined two ammonium ions, and (B) NPEO17 and NPEO19 combined one ammonium ion. (Now Figure S2)
Figure 8. Multiple reaction-monitoring chromatograms of HPLC-MS/MS for blank tea samples spiked at the middle concentration of OPEOs and NPEOs. (Now Figure S2)
- Figure 3 is unreadable, maybe from all figures make two for example: a) OPEO, b) NPEO.
Response:
We thank the reviewer for raising this question. We have added detailed data to describe the Figure 3. (Now Figure 1). We also neglected the description of Figure 4 (now Figure 2) and have now added the data description. (Line 116, 118-120, page 3)
- Whether spaces are needed after the colon? line18-23 page 5
Response:
We are so graceful for your kind question. We have deleted the spaces after the colon. (Line 119-125, page 3)
- Shouldn't the stoichiometric indices in the formulas be in subscript? Figure 5 and 6
Response:
Thank you for your question. We have improved the Figure 5 (Now Figure 3) and Figure 6 (Now Figure 4). We tried to subscript the numbers in the formula, but that would make the numbers too small to be clear, so we simply wrote the numbers of the ethoxylation units and labeled the compound categories in each diagram. (Page 6)
- Was the validation of the method carried out according to some guide? If yes, with what document. If not, what are the acceptable validation parameters and from where they were taken?
Response:
We thank the reviewer for raising this question. Our method carried out according to a Chinese national standard. We have added a sentence to clarify this. (Line 243-245, page 10)
- The results and discussion include some elements of comparison with another methods, but not enough. Authors should describe advantages of the method compared to other reported methods. Can prepare a table with a short description of methods optimized by other researchers.
Response:
We thank for the reviewer recommendation. We have added a table (Table 1) to compare with reported methods. (Page 7-8)
- I think that figure 8 „Concentration of…” should be figure 9. Please, change the numer of figure in the text and under the figure.
Response:
Thank you for your kind question. We have corrected it (Now Figure 6). (Line 190, page 8)
- Different types of tea were studied, so the following question arises: was there any correlation noted for the occurrence of any of the tested compounds in a particular type of tea? (section 2.4)
Response:
We thank the reviewer for raising this question. After classification of tea samples, the small quantity is not convincing. And the relationship between tea types and APEOs residues is not analyzed in paper. Hence, we decide to delete the information on the quantity of different types of tea and combined sample collection and extraction and clean-up. (Section 4.3, page 9-10).
- What type of tea was used for validation and why?
Response:
Thank you for this valuable feedback. We choose green tea for validation, because it is the most productive tea in China. We have added sentences in details to clarify these questions in Section 4.2. (Line 231-238, page 10)
- I know that the authors plan to assessment of dietary intake in the future. However, my question is why not do it in this work. It would increase the value of this work.
Response:
We regret that risk assessment of dietary intake is not covered in the article. If a dietary risk assessment is carried out, a test for APEOs content in tea soup is required. (We consume APEOs by drinking tea soup.) The matrix of tea soup is completely different from that of tea, which requires the establishment of a new validation method. The overall workload has more than doubled, which cannot be completed in a short time.
- Preparing references is not in accordance with the requirements of the journal. Titles of articles should be abbreviated and capitalized: Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal NameYear, Volume, page range.
Response:
Thank you for pointing that out. We have carefully revised the references according to the requirements of the journal. (References, page 11-13)
- Please, corrected the word „china” line 106 page 15; the abbreviation “quechers” line 71 page 17 Please, check all position in references very carefully.
Response:
Thank you for pointing that out. We have carefully revised them. (Line 341, page 12; Line 395, page 13)
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors established an SPE–UPLC–MS/MS analytical method for determining APEO3–20 (total 36 monomers) residues. In general, the analysis method was successfully established. However, there are a few issues that the author should pay attention to.
(1) What are the application scenarios of this detection method? Is there a certain limitation？
(2) All the figures in the article are not annotated with significance analysis, which may create a data blind spot for readers when reading the article.
(3) In statistical analysis, significance analysis methods should be added and all significance analyses in the graphs should be annotated.
(4) Please move the formulas in statistical analysis to the methods section.
(5) This manuscript only establishes one detection method, while the information on the detected molecule's structural property, functional property, and biological activity is not known. Do you think this is consistent with the goal of publishing articles in Molecules?
Author Response
Please see the attached file
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsAccept
Author Response
Dear reviewer，
Thank you very much for your valuable time in commenting on this article.
Best regards.
Qin Lin
