Determination of Eugenol Residues in Fish Tissue, Transport, and Temporary Water of Aquatic Product by Gas Chromatography–Tandem Mass Spectrometry with Application of the Electrospun Nanofibrous Membrane
and Zhengquan Wang 1,2,*Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsAfter reviewing the manuscript titled "Determination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatog-raphy-tandem mass spectrometry with application of electro-spun nanofibrous membrane", I have the following comments.
1. There are several typos and minor typing issues throughout the manuscript. In the first page of the manuscript, it seems like the name of an author is missing.
2. There a re several issues with the way text is cited. For example, the first reference does not correspond to the claims made in the first sentence itself. Same issue persists for references 2-4. None of these references talk about dental applications. It is suggested to revise most of the references and include latest research articles and review papers for several texts in the introduction section.
3. Since Figure 2 is in black and white, it is impossible to discern the different components of Figure 2b.
4. The extraction method needs to be compared with a commonly used or commercially available method for strengthening the arguments and to make the research more convincing.
Comments on the Quality of English LanguageThere are several typographical errors throughout the manuscript. a thorough proof reading is required.
For example, Table 3, "Matri effect" for "Matrix Effect", "Fish tisscue" for "Fish Tissue".
Line: 188-189 : "Isoeu-genol is mainly converted to isoeugenol..." does not make any sense.
Also, several sentences require rephrasing in order to make sense.
Author Response
Reviewer comments:
Reviewer #1 (Comments for the Author):
Comments and Suggestions for Authors
After reviewing the manuscript titled "Determination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatog-raphy-tandem mass spectrometry with application of electro-spun nanofibrous membrane", I have the following comments.
Response: Thank you.
- There are several typos and minor typing issues throughout the manuscript. In the first page of the manuscript, it seems like the name of an author is missing.
Response: Thank you for your comment. This part has been corrected.
- There are several issues with the way text is cited. For example, the first reference does not correspond to the claims made in the first sentence itself. Same issue persists for references 2-4. None of these references talk about dental applications. It is suggested to revise most of the references and include latest research articles and review papers for several texts in the introduction section.
Response: Thank you for your comment. All ref has been updated, and the text has been further revised to improve the writing.
- Since Figure 2 is in black and white, it is impossible to discern the different components of Figure 2b.
Response: Thank you for your comment and suggestion. Figure 2 has been changed to a color figure. Please refer to line 280.
- The extraction method needs to be compared with a commonly used or commercially available method for strengthening the arguments and to make the research more convincing.
Response: Thank you for your comment and suggestion. Comparisons have been made in the main text. Please refer to line 75-85 and line 221-224.
- Comments on the Quality of English Language
There are several typographical errors throughout the manuscript. a thorough proof reading is required.
For example, Table 3, "Matri effect" for "Matrix Effect", "Fish tisscue" for "Fish Tissue".
Line: 188-189 : "Isoeu-genol is mainly converted to isoeugenol..." does not make any sense.
Also, several sentences require rephrasing in order to make sense.
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper.
Please do not hesitate to contact me if you require further information.
Yours sincerely,
Zheng-quan Wang
Associate Prof. Dr. Zheng-quan Wang
College of Food Science and Technology
Shanghai Ocean University
No. 999, Hucheng Ring Road, Lingang New City, Pudong New District
Shanghai 201306, China
E-mails: [email protected]；[email protected]
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsEugenol is used to sedate fish during transport. Eugenol is an approved fish anesthetic in some countries, but not others. The EU regulates the amount of isoeugenol in fish tissue. The authors describe a method to detect eugenol in the transport water and temporary water (TATW) and fish tissues. Fish tissue is difficult to rapidly filter due to clogging. The authors describe an electrospun nanofiber membrane (ENM) to filter a fish tissue homogenate that does not clog during fish tissue homogenate filtration. They identified a stable and inexpensive internal standard, p-terphenyl (Ter) and developed a GC-MS method to detect and quantify the amount of eugenol and isoeugenol in TATW and tissue. They applied this method to TATW and/or tissue samples from 315 Chinese samples.
The manuscript should be edited to improve its readability and remove inconsistencies. Some of the tables and figures need to be revised to make them clearer. Some of the specific corrections are listed below.
The authors need to carefully proofread the manuscript to remove spelling and grammatical errors and unnecessary repetition. The authors need to resolve inconsistencies in the introduction. At the end of the first paragraph, the authors state that there is “no legal withdrawal period”. At the end of paragraph 2, they state that “[in Japan]…the withdrawal time should be 7 days in 2014”. Reference 11 states that, as of 2014, China has not approved any fish anesthetics. The EU regulations (363/2011; reference 11) call for a maximum level of isoeugenol of 6 mg/kg in fin fish.
Please define acronyms or initialisms, such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and UAE, the first time they are used.
Line 188-189 “Isoeugenol is mainly converted to isoeugenol” is confusing.
Line 195 suggests 14C-eugenol as an internal standard. 14C is radioactive; 13C is a stable isotope. Do the authors mean 13C? 13C-eugenol would be a better choice.
On line 271, the authors state “for each pesticide”. The reviewer assumes that this is clove oil or eugenol, but the authors should clarify what they mean.
The authors state in lines 290-291 that their “LOD and LOQ of 0.5 and 1.5 μg/L also were better than the previous values of 0.4-51.0 μg/L and 1.2-2000 μg/L”. A more accurate description is that the GC/MS method described in reference 31 is comparable to the results described in this work.
Reference 44 (line 489) lists an author as R⫲žička. The name should be Růžička.
Table 2d is confusing.
The data in the columns do not line up.
There are two columns [RSD (%) (Inter-day recoveries, n = 6)] with three numbered columns each (10, 20, 50). The difference between the two sets of columns is unclear. One set of column heads is bolded and the other is not. The reason is not explained. Presumably they represent TATW and FT.
Table 3 is confusing.
The mean ± SD should be on the same line. The column headings should all be in bold or not. If there is a reason for bolding some columns, then that reason should be stated.
Table 4: The initialisms AQS, TRWS, and TEWS are used but not defined.
Figure 4 (a) and (b): The graphs should be offset, so the reader can interpret them. As presented, the data is unnecessarily confusing.
Figure 5: The graphs of FT and TATW samples are on the same axis and difficult to read. They should be offset, so the reader can interpret them. The authors state the samples are blanked, yet they appear to contain some amount of sample. The caption for the figure describes two very different FT and TATW LVI injection series (a-c; g-i) but the authors do not indicate how the two series differ. The figures show different peaks, but the peaks are not identified.
Comments on the Quality of English LanguageThe authors need to carefully proofread the manuscript to remove spelling and grammatical errors and unnecessary repetition. The authors need to resolve inconsistencies in the introduction. At the end of the first paragraph, the authors state that there is “no legal withdrawal period”. At the end of paragraph 2, they state that “[in Japan]…the withdrawal time should be 7 days in 2014”. Reference 11 states that, as of 2014, China has not approved any fish anesthetics. The EU regulations (363/2011; reference 11) call for a maximum level of isoeugenol of 6 mg/kg in fin fish.
Please define acronyms or initialisms, such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and UAE, the first time they are used.
Line 188-189 “Isoeugenol is mainly converted to isoeugenol” is confusing.
Line 195 suggests 14C-eugenol as an internal standard. 14C is radioactive; 13C is a stable isotope. Do the authors mean 13C? 13C-eugenol would be a better choice.
On line 271, the authors state “for each pesticide”. The reviewer assumes that this is clove oil or eugenol, but the authors should clarify what they mean.
Author Response
Reviewer #2 (Comments for the Author):
Eugenol is used to sedate fish during transport. Eugenol is an approved fish anesthetic in some countries, but not others. The EU regulates the amount of isoeugenol in fish tissue. The authors describe a method to detect eugenol in the transport water and temporary water (TATW) and fish tissues. Fish tissue is difficult to rapidly filter due to clogging. The authors describe an electrospun nanofiber membrane (ENM) to filter a fish tissue homogenate that does not clog during fish tissue homogenate filtration. They identified a stable and inexpensive internal standard, p-terphenyl (Ter) and developed a GC-MS method to detect and quantify the amount of eugenol and isoeugenol in TATW and tissue. They applied this method to TATW and/or tissue samples from 315 Chinese samples.
Response: Thank you very much for your comment.
1.The manuscript should be edited to improve its readability and remove inconsistencies. Some of the tables and figures need to be revised to make them clearer. Some of the specific corrections are listed below.
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper. Also, all tables and figures were revised.
2.The authors need to carefully proofread the manuscript to remove spelling and grammatical errors and unnecessary repetition. The authors need to resolve inconsistencies in the introduction. At the end of the first paragraph, the authors state that there is “no legal withdrawal period”. At the end of paragraph 2, they state that “[in Japan] the withdrawal time should be 7 days in 2014”. Reference 11 states that, as of 2014, China has not approved any fish anesthetics. The EU regulations (363/2011; reference 11) call for a maximum level of isoeugenol of 6 mg/kg in fin fish.
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper. In addition, we removed unnecessary repetition and eliminated the inconsistency in the introduction section.
3.Please define acronyms or initialisms, such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and UAE, the first time they are used.
Response: Thank you for your suggestion. This part has been corrected. Please refer to line 82-84.
4.Line 188-189 “Isoeugenol is mainly converted to isoeugenol” is confusing.
Response: Thank you for your comment. We meant that “eugenol and isoeugenol could be interconverted with each other”. We have removed this ambiguous statement.
5.Line 195 suggests 14C-eugenol as an internal standard. 14C is radioactive; 13C is a stable isotope. Do the authors mean 13C? 13C-eugenol would be a better choice.
Response: Thank you for your comment and suggestion. Actually, the references cited in the manuscript refer to eugenol labelled with 14C, without the use of 13C. In this study, we chose Ter. Please refer to line 305-307.
6.On line 271, the authors state “for each pesticide”. The reviewer assumes that this is clove oil or eugenol, but the authors should clarify what they mean.
Response: Thank you for this. We apologize for the mistake. This part was corrected. Please refer to line 391.
7.The authors state in lines 290-291 that their “LOD and LOQ of 0.5 and 1.5 μg/L also were better than the previous values of 0.4-51.0 μg/L and 1.2-2000 μg/L”. A more accurate description is that the GC/MS method described in reference 31 is comparable to the results described in this work.
Response: We are very grateful to the reviewer for this suggestion. We have corrected this part. Please refer to line 410-411.
8．Reference 44 (line 489) lists an author as R⫲žička. The name should be Růžička.
Response: We are very grateful to the reviewers for pointing this out. We apologize for the error. This part has been corrected. Also, a new reference has been added.
9.Table 2d is confusing. The data in the columns do not line up. There are two columns [RSD (%) (Inter-day recoveries, n = 6)] with three numbered columns each (10, 20, 50). The difference between the two sets of columns is unclear. One set of column heads is bolded and the other is not. The reason is not explained. Presumably they represent TATW and FT.
Response: This is a very good question. Thank you. The column on the left indicates the inter-day recovery rate and the right shows the intra-day recovery rate. After careful inspection, we decided that the column headers should not be bolded. The data in the table are presented as TATW/FT; for example, the first data 3.6/3.4, 3.6 refers to TATW while 3.4 refers to FT. We have combined the data of TATW and FT into one table, and there should be two columns for either the data of TATW or the data of FT alone, one for the inter-day recovery rate and the other for the intra-day recovery rate. Please refer to Table 2.
10.Table 3 is confusing.The mean ± SD should be on the same line. The column headings should all be in bold or not. If there is a reason for bolding some columns, then that reason should be stated.
Response: Thank you for your comment. We apologize for the format error. We have corrected the table after reviewing the references published in the last two years. Please refer to Table 3.
11.Table 4: The initialisms AQS, TRWS, and TEWS are used but not defined.
Response: Thank you for your comment. We apologize for this. We added this part. Please refer to Table 4.
12.Figure 4 (a) and (b): The graphs should be offset, so the reader can interpret them. As presented, the data is unnecessarily confusing.
Response: Thank you for your comment and suggestion. We fully accept this constructive suggestion. Thus, this part has been modified. Please refer to Figure 4 (a) and (b).
13.Figure 5: The graphs of FT and TATW samples are on the same axis and difficult to read. They should be offset, so the reader can interpret them. The authors state the samples are blanked, yet they appear to contain some amount of sample. The caption for the figure describes two very different FT and TATW LVI injection series (a-c; g-i) but the authors do not indicate how the two series differ. The figures show different peaks, but the peaks are not identified.
Response: Thank you for your comment. We fully agree with your suggestion. Thus, this part has been modified. Please refer to Figure 5.
In addition, by blanked, we mean a matrix blank of fish and water samples that do not contain eugenol.
Thank you. The different descriptions of the two series have been annotated under the figure. Please refer to line 370.
The peaks have been identified. Please refer to Figure 5.
14.Comments on the Quality of English Language
The authors need to carefully proofread the manuscript to remove spelling and grammatical errors and unnecessary repetition. The authors need to resolve inconsistencies in the introduction. At the end of the first paragraph, the authors state that there is “no legal withdrawal period”. At the end of paragraph 2, they state that “[in Japan]…the withdrawal time should be 7 days in 2014”. Reference 11 states that, as of 2014, China has not approved any fish anesthetics. The EU regulations (363/2011; reference 11) call for a maximum level of isoeugenol of 6 mg/kg in fin fish.
Response: Thank you. Please refer to response 2.
15.Please define acronyms or initialisms, such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and UAE, the first time they are used.
Response: Thank you. Please refer to response 3.
16.Line 188-189 “Isoeugenol is mainly converted to isoeugenol” is confusing.
Response: Thank you. Please refer to response 4.
17.Line 195 suggests 14C-eugenol as an internal standard. 14C is radioactive; 13C is a stable isotope. Do the authors mean 13C? 13C-eugenol would be a better choice.
Response: Thank you. Please refer to response 5.
18.On line 271, the authors state “for each pesticide”. The reviewer assumes that this is clove oil or eugenol, but the authors should clarify what they mean.
Response: Thank you. Please refer to response 6.
Please do not hesitate to contact me if you require further information.
Yours sincerely,
Zheng-quan Wang
Associate Prof. Dr. Zheng-quan Wang
College of Food Science and Technology
Shanghai Ocean University
No. 999, Hucheng Ring Road, Lingang New City, Pudong New District
Shanghai 201306, China
E-mails: [email protected]；[email protected]
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsThe article entitled "Determination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatography-tandem mass spectrometry with application of electrospun nanofibrous membrane" is time-relevant and can be part of the modern assessment in the fields of environmental protection and material engineering relevant to food science.
Therefore, some suggestions are in the following lines:
- delete "corresponding author" in the Correspondance line after the Authors name
- Extensive English corrections must be included in a revised version of this article
- I strongly believe that Table 1 can not be part of the introduction, but this table can be a base for better discussion in the following parts of the paper. So, I suggest revising the Introduction and making it without the mentioned table, but also expanding and revising the comparison of the obtained results with more references, etc.
- Consequently, references (numbering and the final list) have to be revised.
- Section 2.7. Data Analysis has to include more details about the implemented mathematical tools
- I am not sure after the first reading of the paper that the experimental concept is presented in the initial part of the paper. I suggest adding some kind of graphical/schematic presentation of the experimental steps before subsections in the Materials and Methods section.
- Better highlighting the further steps in the Conclusions part has to be added.
Comments on the Quality of English Language
Extensive editing of English language required
Author Response
Reviewer # 3 (Comments for the Author):
Comments and Suggestions for Authors
The article entitled "Determination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatography-tandem mass spectrometry with application of electrospun nanofibrous membrane" is time-relevant and can be part of the modern assessment in the fields of environmental protection and material engineering relevant to food science.
Response: Thank you very much for your comment.
Therefore, some suggestions are in the following lines:
- delete "corresponding author" in the Correspondance line after the Authors name
Response: Thank you for your suggestion. This "corresponding author" has been deleted. Please refer to line 11.
- Extensive English corrections must be included in a revised version of this article
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper.
- I strongly believe that Table 1 can not be part of the introduction, but this table can be a base for better discussion in the following parts of the paper. So, I suggest revising the Introduction and making it without the mentioned table, but also expanding and revising the comparison of the obtained results with more references, etc.
Response: Thanks for your comments and suggestions, we also strongly agree with your point of view. But we insist keep the Table 1 in the Introduction, is for the purpose to control the length and to minimize the presence of more descriptive text.
- Consequently, references (numbering and the final list) have to be revised.
Response: Thank you for your suggestion. We agree with the reviewer. Thus, references (numbering and the final list) has been appropriately adjusted.
- Section 2.7. Data Analysis has to include more details about the implemented mathematical tools
Response: Thank you for your suggestion. We decide follow with opinin of reviewer 5, and Section 2.7 Data Analysis has been deleted.
- I am not sure after the first reading of the paper that the experimental concept is presented in the initial part of the paper. I suggest adding some kind of graphical/schematic presentation of the experimental steps before subsections in the Materials and Methods section.
Response: Thank you for the great constructive opinion. We have added graphical presentation as an Annex. Please refer to Annex 2.
- Better highlighting the further steps in the Conclusions part has to be added.
Response: Thank you for the comment. We agree with the reviewer and we have rewritten “The Results and Discussion”.
Comments on the Quality of English Language
Extensive editing of English language required
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper.
Please do not hesitate to contact me if you require further information.
Yours sincerely,
Zheng-quan Wang
Associate Prof. Dr. Zheng-quan Wang
College of Food Science and Technology
Shanghai Ocean University
No. 999, Hucheng Ring Road, Lingang New City, Pudong New District
Shanghai 201306, China
E-mails: [email protected]；[email protected]
Author Response File: Author Response.docx
Reviewer 4 Report
Comments and Suggestions for AuthorsSee the attached file
Comments for author File: Comments.docx
Author Response
Reviewer #4 (Comments for the Author):
The article submitted for review presents a simple, rapid, and sensitive methodology for quantifying eugenol residues in fish tissue and water samples using gas chromatography-tandem mass spec-trometry and electrospun nanofibrous membrane.
After reading and studying the manuscript, I came to some conclusions. There are a number of aspects that need to be reviewed. Below are the main points that I think should be reviewed and my comments.
Response: Thank you very much for your comment.
Page 1. Introduction: “MS-222”
Comment 1: Specify what “MS-222” means.
Response: Thank you for the comment. “MS-222” is a kind of “fish anesthetics”, as descibed in line 40.
Page 2, Last line: “P(DLLA-CL)”
Comment 2: Specify what “P(DLLA-CL)” means. I suppose: “homoconjugate D,L-lactic acid and ε-caprolactone”.
Response: Thank you for the comment. You supposd it right, it is indeed“homoconjugate D,L-lactic acid and ε-caprolactone”, we have already added the full name when its abbreviation first appeared.
Page 4, first two lines: “… or water samples… until …past two years.”
Comment 3: Write these two lines after the last line from page 3
Response: Thank you for the comment. We have rewritten that paragraph.
All pages:
Comment 4: Number all the pages in a row, not each section. This happens when changing the page format from Portrait to Landscape and vice versa.
Response: Thank you for the comment and the suggestions. All the line number has been reset.
Page 4: Table 1
Comment 5: In table 1, try to adjust the font size so that the information in a cell appears on a single line
Response: Thank you for the comment and the suggestions. We changhed table 1 as the way you mentioned.
Page 5, Lines 9-10:
Comment 6: “CAN – acetonitrile” appear twice, both on lines 9 and 10
Response: Thank you for the comment. This mistakes have been corrected.
Page 6, Lines 34-43:
Comment 7: I don't think that in the section "2.3. Apparatus" the conditions for analysis by GC-MS/MS should be specified. For this I suggest a separate paragraph
Response: Thank you for the comment and the suggestions. We seprated 2.3 into two parts.
Page 7, Line 90: “The QuEChERS and UAE extraction”
Comment 8: I suggest to explain what "QuEChERS" and “UAE” means: QuEChERS – a type of dispersive solid phase extraction, that stands for ‘Quick, Easy, Cheap, Effective, Rugged and Safe’; UAE – Ultrasound-assisted extraction.
Response: Thank you for your suggestion. This part has been corrected. Please refer to line 82-84.
Page 10: Figure 2
Comment 9: I suggest increase the images resolution or size (for example in Figure 2 h and i, the order of magnitude is not visible in the two images; Figures 2 j and k are not very clear)
Response: Thank you for the comment and the suggestions. We improved the images resolution.
Page 11: Figure 3
Comment 10: I suggest increase the images resolution (what is written is not clearly visible).
Response: Thank you for the comment and the suggestions. We improved the images resolution.
Page 12: Figure 4
Comment 11: I suggest increase the images resolution (what is written is not clearly visible).
Response: Thank you for the comment and the suggestions. We improved the images resolution.
Page 12, Line 236: “…equation was Y = -0.0617 + 0.1208X with …”
Comment 12: I suggest that in the given equation it should be specified what Y and X means. I assume that X represents the concentration (to write and the unit, I suppose mg/L) and Y represents the Peak area (or its height).
Response: Thank you for the comment. We added meaning in parentheses.
Page 13, Table 2 (b): Equations
Comment 13: I suggest that in table 2 (b) to replace X and Y from the equation with the corresponding meaning (see the previous comment)
Response: Thank you for the comment. We added meaning in parentheses in table 2 (b).
Page 13, Table 2 (b): Response f
Comment 14: NOMAL = ?
Response: Thank you for the comment. We change “NOMAL” to “High”.
Page 13, Table 2 (c): “Recoveries ± RSD (%)”
Comment 15: At page 13, lines 251-252 appear “mean of sextuplicate analyses ± standard deviation”. See Comment 17. Please, make the correct change. I suggest “Recoveries ± SD”.
Response: Thank you for the comment. We corrected it.
Page 13, Table 2 (d): “RSD (%), Intra-day and Inter-day recoveries”
Comment 16: If the numerical data in Table 2 (d) represent the RSD value, then these are not intra- and inter-day recoveries (these should be around 100%), they represent intra- and inter-day precision (Repeatability and Intermediate Precision, according to the ICH Q2(R1) guideline). See also the line 285, paragraph 3.5., page 15
Response: Thank you for your comment, these data represent intra- and inter-day precision, which has been corrected, please refer to Table 2
Page 13, Lines 251-252: “Spiking level (μg/L)g: mean of sextuplicate analyses ± standard deviation;”
Comment 17: In table 2 (c) appear “± RSD (%)” not “± standard deviation (SD)”. Please, make the correct change.
Response: Thank you for the comment. We corrected it.
Page 14: Figure 5
Comment 18: I suggest increase the images resolution (what is written is not clearly visible).
Response: Thank you for the comment and the suggestions. We improved the images resolution.
Page 14: Table 3
Comment 19: In table 3, columns 3 - 8, try to adjust the font size so that the values from a cell appears on a single line
Response: Thank you for the comment and the suggestions. We corrected it table 3.
Comment 20: In Table 3, first column, second row - write “Matrix” instead of “Matri” and “Fish tissue” instead of “Fish tisscue”.
Response: Thank you for the comment. This two word have been corrected This part has been corrected in table 3.
Page 15, 280: “Figure4”
Comment 21: Write a blank between Figure and 4
Response: Thank you for the comment. We added.
Page 15, Line 285: “The inter-day and intraday precisions”
Comment 22: I suggest: "The RSD (%) values for inter-day and intraday precisions"
Response: Thank you for the comment and the suggestions. We accept to use the above expression way.
Page 15, Line 301: “Table A presents affirmative…”
Comment 23: I suggest “Table 4 presents affirmative…” or “Table 4 (a-c) presents affirmative…”
Response: Thank you for the comment. We accept to use “Table 4 (a-c) presents affirmative…”.
Provided the issues listed above are resolved, the paper is worthy of publication.
Please do not hesitate to contact me if you require further information.
Yours sincerely,
Zheng-quan Wang
Associate Prof. Dr. Zheng-quan Wang
College of Food Science and Technology
Shanghai Ocean University
No. 999, Hucheng Ring Road, Lingang New City, Pudong New District
Shanghai 201306, China
E-mails: [email protected]；[email protected]
Author Response File: Author Response.docx
Reviewer 5 Report
Comments and Suggestions for AuthorsDetermination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatography-tandem mass spectrometry with application of electrospun nanofibrous membrane
Overall comments:
This study primarily focuses on determining eugenol in fish samples collected from markets in the Shanghai, Zhejiang, and Fujian provinces of China. To conduct sample analysis, the study developed a sample preparation method using electrospun nanofibrous membrane. The research results are categorized into two main content groups: 1/ Optimization of sample preparation and analysis conditions on the equipment and 2/ Analysis results of fish samples. However, this manuscript is presented in a rather unclear manner. The content does not align well with the section headings. The paper's results lack in-depth discussion and show limited innovation to yield a robust research outcome.
Specific comments:
1. The manuscript title needs to be revised to be more general and specific. As the paper has not identified a specific research objective, naming the paper is challenging. 2. The abstract is quite rudimentary. The results after optimizing the analysis conditions should be included in this section. The abstract does not provide an overview of the research results. Concluding the results of 315 fish samples with statements about their content as presented in the abstract is too simplistic. The analysis method using GC/MS cannot be considered a screening model; thus, the statement "It can be considered a screening model for analysis" is inappropriate.
2. The introduction should specify how many eugenol compounds there are, demonstrating why this study chose only two compounds, eugenol and isoeugenol, for investigation. The study does not convincingly explain why the ENM method was used for sample processing instead of similar extraction methods used in previous research. Table 1 needs better presentation for readability. Check abbreviations like ACN (acetonitrile) as they seem to be autocorrected to CAN. The introduction needs a clear presentation of the research objective.
3. The Sample Collection section needs a detailed description of the sampled markets and the number of samples. What is the sample water volume? More details about the sampling process are needed. Information about the samples is crucial but is not presented well, such as fish type, length, and weight. Section 2.5 Procedure should be deleted. The recovery efficiency needs detailed presentation—how is it determined, and is it related to the internal standard? Why choose p-terphenyl as the internal standard? Typically, an internal standard is an isotopic standard; if the internal standard is not an isotopic standard, it can only reduce the error of the injection volume, not the error in sample preparation, as it is not an internal surrogate. Section 2.7 Data Analysis could be removed as it is presented too simplistically.
4. The Results and Discussion section is the main part but is presented with many errors and is difficult to understand, seemingly not conveying the research results well.
From lines 80-119 in Section 3.1 Optimization of the Extraction of Eugenol, the content is presented like an introduction, so it should be moved to the introduction. This part needs to discuss the research results, but there is no discussion on Optimization of the Extraction. Unclear how the study was conducted; values that need optimization, such as ACN, TCM, HEX, are not explained. Surveying the fraction of extraction to ensure Eugenol remains after ENM filtration needs clarification. Explain the use of TCM, HEX, NaCl, MgSO4 in the process.
Similarly, lines 126-154 of Section 3.2 Application of ENM are presented like an introduction and should be moved to the introduction. This section relates to the application of ENM, but Figure 2 is labeled Preparation and characterization.
Similarly, lines 184-199 of Section 3.3 Optimization of ISTD should also be moved to the introduction. However, the study on optimization of the internal standard is illogical. The results indicate that storing standard and internal standard should be under 4 months, which is unrelated to this paper's research.
Optimization of Injection Mode in Section 3.4 is one of the minor results of the study. This needs no detailed presentation as this is a common practice in analytical chemistry. However, errors can be eliminated using an internal standard, so there is no need to present it as a research content.
The study has not published LOD and LOQ values. The published values in the paper are IDL (Instrument Detection Limit) and IQL (Instrument Quantification Limit). Spike samples appear to have only been performed with water or solution samples, not with fish samples. The study did not perform blank and CRM samples, so the results of the validation method are not convincing. The evaluation of matrix effect is very unclear.
Results for the 315 samples should be presented in graphs to show the use of eugenol in different areas. It needs to classify fish types, weight, and size. Explain what types AQS, TRWS, TEWS are. It is not appropriate to present the concentration of eugenol in AQS samples and TEWS samples in the same table with the same unit (ug/L) because the unit of AQS must be ug/kg. Present it more clearly to show the difference between tables a, b, c of Table 4. Conclusions do not show a correlation between eugenol levels in water and in fish.
5. The conclusion presented is quite rudimentary and does not summarize the research results well.
6. The manuscript cites 45 references. However, there are many articles related to eugenol analysis that also need to be cited to provide a comprehensive overview of relevant studies in the introduction.
7. The manuscript has many English language errors that need correction.
Conclusion:
Apparently, this study aims to evaluate the use of eugenol as an anesthetic in the transportation of fish and seafood, leading to aquatic products containing residual eugenol. However, the presentation of the research results in the paper does not convey this information. The results are presented in a disorganized manner and lack significance. The paper needs a complete revision; otherwise, it will not be suitable for publication in the Foods journal.
Comments on the Quality of English LanguageThe manuscript has many English language errors that need correction.
Author Response
Reviewer #5 (Comments for the Author):
Specific comments: The manuscript title needs to be revised to be more general and specific. As the paper has not identified a specific research objective, naming the paper is challenging. 2. The abstract is quite rudimentary. The results after optimizing the analysis conditions should be included in this section. The abstract does not provide an overview of the research results. Concluding the results of 315 fish samples with statements about their content as presented in the abstract is too simplistic. The analysis method using GC/MS cannot be considered a screening model; thus, the statement "It can be considered a screening model for analysis" is inappropriate.
Response: Thank you for your comment and suggestion.
(1) The manuscript title has been revised to “Determination of eugenol residues in fish tissue, transport and temporary water of aquatic product by gas chromatog-raphy-tandem mass/mass spectrometry with application of the electrospun nanofibrous membrane”.
(2) The abstract has been revised. Please refer to line 12-25. We have also uploaded an attachment regarding the results of the 315 positive samples; please refer to Annex 1 and Annex 2.
2.The introduction should specify how many eugenol compounds there are, demonstrating why this study chose only two compounds, eugenol and isoeugenol, for investigation. The study does not convincingly explain why the ENM method was used for sample processing instead of similar extraction methods used in previous research. Table 1 needs better presentation for readability. Check abbreviations like ACN (acetonitrile) as they seem to be autocorrected to CAN. The introduction needs a clear presentation of the research objective.
Response: Thank you for the comment and all the suggestions.
(1) The introduction section has been revised to improve the writing. According to an investigation by the Chinese government, there is an overabundance of eugenol in China, and eugenol residues continue to be detected in the aquatic market, but not MS-222. Thus, we chose only eugenol for further testing. Because isoeugenol and eugenol are both present in eugenol essential oil, we also analyzed isoeugenol. We tried isoeugenol as an internal standard but found that eugenol is converted to isoeugenol, so we ended up using Ter.
(2) We have added a detailed explanation of the reasons for processing samples using the ENM method. Please refer to line 263-267.
(3) We agree with the reviewer. Thus, Table 1 has been appropriately adjusted.
(4) This part has been corrected. Please refer to line 78, 207-210 and Table 1.
(5) The introduction section has been revised to improve the writing. Please refer to line 114-117.
3.The Sample Collection section needs a detailed description of the sampled markets and the number of samples. What is the sample water volume? More details about the sampling process are needed. Information about the samples is crucial but is not presented well, such as fish type, length, and weight. Section 2.5 Procedure should be deleted. The recovery efficiency needs detailed presentation—how is it determined, and is it related to the internal standard? Why choose p-terphenyl as the internal standard? Typically, an internal standard is an isotopic standard; if the internal standard is not an isotopic standard, it can only reduce the error of the injection volume, not the error in sample preparation, as it is not an internal surrogate. Section 2.7 Data Analysis could be removed as it is presented too simplistically.
Response: Thank you for the comment and all the suggestions.
(1) Please refer to line140. More information, such as fish type, length, and weight was uploaded to the supplementary section. Please refer to Annex 1 and Annex 2.
(2) This part has been deleted.
(3) This following text has been added: “Although accurate analytical methods must be utilized in the certified reference materials as standard (e.g., using isotopic internal standards has been recognized as a primary measurement method), the high price of isotopic internal standards is unsuitable for economically underdeveloped regions and institutions. Isomers or other substitutes of standard materials can effectively reduce the cost of large-scale food safety screening by government agencies and meet their basic needs for rapid and large-scale testing.” (see line 292-298)
Ter was identified as a stable and inexpensive internal standard.
(4) Section 2.7 Data Analysis has been deleted.
4.The Results and Discussion section is the main part but is presented with many errors and is difficult to understand, seemingly not conveying the research results well.
Response: Thank you for the comment. We have rewritten “The Results and Discussion”.
From lines 80-119 in Section 3.1 Optimization of the Extraction of Eugenol, the content is presented like an introduction, so it should be moved to the introduction. This part needs to discuss the research results, but there is no discussion on Optimization of the Extraction. Unclear how the study was conducted; values that need optimization, such as ACN, TCM, HEX, are not explained. Surveying the fraction of extraction to ensure Eugenol remains after ENM filtration needs clarification. Explain the use of TCM, HEX, NaCl, MgSO4 in the process.
Response: Thank you for the comment and all the suggestions.
(1) We agree with the reviewer. We have moved part of Section 3.1 to the introduction section and added new results and discussion. Please refer to lines 207-214.
(2) The discussion has been added. Please refer to line 209-217. More details please refer to our previous study for more optimization information in this section. Please refer to reference 42.
(3) In our experiments, we have found that the second filtration leaves almost no residue of eugenol. Please refer to line 213-214.
(4) This part has been added. In the extraction process, TCM is located in the upper layer, and HEX is located in the lower layer. NaCl is present for salting out, and MgSO4 removes water from the matrix. Please refer to line 203-209.
Similarly, lines 126-154 of Section 3.2 Application of ENM are presented like an introduction and should be moved to the introduction. This section relates to the application of ENM, but Figure 2 is labeled Preparation and characterization.
Response: Thank you for this question. We agree with the reviewer. We have moved part of Section 3.2 to introduction section and added new results and discussion.
We apologize for the lack of clarity. Actually, the application of ENM is related to Figure 1. We've changed the title. Please refer to Figure 1.
Similarly, lines 184-199 of Section 3.3 Optimization of ISTD should also be moved to the introduction. However, the study on optimization of the internal standard is illogical. The results indicate that storing standard and internal standard should be under 4 months, which is unrelated to this paper's research.
Response: Thank you for the comment. We believe this section helps the reader better understand our study and make a wise choice. For the study on internal standards, we have added a new section. Please refer to line 291-298. In fact, this is just one of the phenomena we have found in our experiments, which we think helps to explain why we chose Ter.
Optimization of Injection Mode in Section 3.4 is one of the minor results of the study. This needs no detailed presentation as this is a common practice in analytical chemistry. However, errors can be eliminated using an internal standard, so there is no need to present it as a research content.
Response: Thank you for the comment. To our knowledge, the optimization of the injection mode is an important part of our study. We found that the large volume injection of 100 µl is not suitable for the quantitative analysis of eugenol in large batches, but then in a 10 µL injection volume, we found that the injection of 5 µL is just as effective and stable. We give up the 100 µL injection volume for the complexity of sample loading, and there is no data display of 100 µL of injection. We found that optimization of the large volume injection volume based on identifying Ter as the internal standard gave better results and was suitable for high-throughput sample loading detection. Our results show that the detection limit can be reduced sharply.
The study has not published LOD and LOQ values. The published values in the paper are IDL (Instrument Detection Limit) and IQL (Instrument Quantification Limit). Spike samples appear to have only been performed with water or solution samples, not with fish samples. The study did not perform blank and CRM samples, so the results of the validation method are not convincing. The evaluation of matrix effect is very unclear.
Response: Thank you for the comment. Please refer to Table 2b.
We made sure that we used a matrix-spiked calibration curve to calculate from the beginning to the end. Thus, LOD and LOQ are for the matrix-spiked experiment, not for the instrument, both the fish tissue samples and water samples.
We did matrix blank spiking experiments, and made sure that our experiments were credible. Please refer to Figure 2.
Thank you, a new expression about the evaluation of matrix effects was added. Please refer to line 372-3811.
Results for the 315 samples should be presented in graphs to show the use of eugenol in different areas. It needs to classify fish types, weight, and size. Explain what types AQS, TRWS, TEWS are. It is not appropriate to present the concentration of eugenol in AQS samples and TEWS samples in the same table with the same unit (ug/L) because the unit of AQS must be ug/kg. Present it more clearly to show the difference between tables a, b, c of Table 4. Conclusions do not show a correlation between eugenol levels in water and in fish.
Response: Thank you for the great constructive opinion. We have graphically represented the results of the 315 samples and the use of eugenol in different regions and uploaded them as an Annex. Please refer to Annex 2. For information related to type, weight, and size of fish, please refer to Annex 1 and Annex 2.
We apologize for the information we forgot. The AQS, TRWS and TEWS notes have been labelled under table 4.
Thank you for pointing out this nuance. This part has been corrected. Please refer to Table 4.
Fig. 4, a, b, c, shows the distribution of positive samples by origin, market and region.
The description has been added to the conclusion. Please refer to line 477-482.
- The conclusion presented is quite rudimentary and does not summarize the research results well.
Response: Thank you for the comment. We have re-summarized the findings and hope that they will meet your requirements.
- The manuscript cites 45 references. However, there are many articles related to eugenol analysis that also need to be cited to provide a comprehensive overview of relevant studies in the introduction.
Response: We agree with the reviewer. We have updated the introduction with new articles related to eugenol analysis.
- The manuscript has many English language errors that need correction.
Response: Thank you for your comment and suggestion. A professional English proofreading company has carefully revised the paper.
Please do not hesitate to contact me if you require further information.
Yours sincerely,
Zheng-quan Wang
Associate Prof. Dr. Zheng-quan Wang
College of Food Science and Technology
Shanghai Ocean University
No. 999, Hucheng Ring Road, Lingang New City, Pudong New District
Shanghai 201306, China
E-mails: [email protected]；[email protected]
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAfter reviewing the updated manuscript, I have the following comments.
The authors have made good improvements in the manuscript. However, still I could see several typos and minor errors. Few of them are highlighted below.
1. In the title "gas chromatography-tandem mass/mass spectrometry" seems weird. Its simply better to use just "gas chromatography-tandem mass spectrometry".
2. Line 35 is unclear. Please rephrase it correctly. "table and wine grapes"
3. Typo in Table 3. "Tisscue for Tissue"
4. Legend of Table 3 : "Matrix Effects"
5. Line 189: Unit of LOQ Level.
Although, I have highlighted few of them, it is strongly suggested to perform another round of proofreading of the entire manuscript.
In figures 2-4, the Y axis of MS data is represented for peak area, whereas in other figures it is intensity. This needs clarification.
Figure 2, j & k are quite important for this manuscript. There are few issues here. There doesn't seem to be much difference in terms of S/N of with and without ENM. Ideally, this could be a separate figure with more clear image. Also, what is the rationale for comparing these compounds at these concentration levels when the linearity is at a different level. Again, the stated linearity concentration units are different in many places (mg/L & µg/L) making it difficult to make sense. The authors need to address this properly.
Comments on the Quality of English LanguageA thorough proofreading of the entire manuscript is required.
Author Response
attached
Author Response File: 
Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors/
Comments on the Quality of English Language/
Author Response
attached
Author Response File: Author Response.docx
Reviewer 4 Report
Comments and Suggestions for AuthorsSee the attached file
Comments for author File: Comments.docx
Author Response
attached
Author Response File: Author Response.docx
Reviewer 5 Report
Comments and Suggestions for AuthorsRevised
Comments on the Quality of English Languageok
Author Response
attached
Author Response File: Author Response.docx
