Simultaneous Determination of Seven Pyrethroid Pesticide Residues in Aquatic Products by Gas Chromatography
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors“Fishes" -
Review of the Manuscript ID: fishes-2856481entitled “
Simultaneous Determination of 7 Pyrethroid Pesticide 2 Residues in Aquatic Products by Gas Chromatography”
The objective of this research is to develop a high-throughput, and readily applicable gas chromatography (GC) method for the simultaneous detection of 7 PYRs (cyhalothrin, permethrin, cyfluthrin, cypermethrin, tau-Fluvalinate, fenvalerate, deltamethrin). In authors' opinion the creation of a method for detecting PYRs residues in aquatic products can be usefull in the aquaculture industry and have significant economic and social advantages.
Currently, existing national and industrial standards for PYR detection mainly focused on the samples of vegetables, fruits, tea and other plant foods.
Althouth aquatic products are important food resources for healthy life, but the presence of different kinds of pesticides, including pyrethroid (PYR) pollutants pose a threat to the consumers’ health.
The optimum experimental conditions were conducted to evaluate the developed Gas chromatography method for quantifying the 7 PYRs using the standard addition method. The method was validated in terms of selectivity, linearity, limit of detection (LOD) and quantitation (LOQ), accuracy and precision.
In the study authors drew attention to development a method for determining selected pyrethroids in raw materials of aquatic origin. There is little information in the literature on the determination of these pesticides in raw materials of aquatic origin. Therefore, in my opinion the developed method can be useful and valuable.
I kindly ask you to clarify the following issues:
1. Line 103 - spacing after "degrees Celsius" is necessary
2. Why these 7 pesticides were chosen for testing ?
3. Please explain why you chose type of samples for study.
4. What internal standard was applied?
5. Could you elaborate on the statement: “The establishment of pyrethroid residue method in aquatic products can not only improve the accuracy of analysis”?
It is recommended that this manuscript should be accepted for publication after major revision.
February 7, 2024.
Author Response
Dear Reviewer:
Thank you for your kind work to our manuscript (fishes-2856481). The manuscript has been revised carefully according to the reviewers’ valuable comments. The responses to the referees’ comments one by one are described as follows:
1) Line 103 - spacing after "degrees Celsius" is necessary.
Response: Thanks. We have made correction accordingly.
2) Why these 7 pesticides were chosen for testing?
Response: Thanks a lot for the carefully review on our manuscript. Pyrethroid pesticides have been applied to agriculture and aquaculture since the 1970s to replace traditional pesticides. Unfortunately, the elimination rate of pyrethroids in aquatic organisms is low, and these compounds can be fatal to aquatic species, especially fish. In order to better monitor pesticide content in aquatic products, we have selected these seven pesticides, which are widely distributed and used in agriculture and aquaculture. The relevant supplement information was also added into the revised manuscript.
3) Please explain why you chose type of samples for study.
Response: Thanks a lot for the carefully review on our manuscript. In order to expand the scope of application of the explored method, multiple types of samples, including fish, shrimp, shellfish, crab and sea cucumber, are selected. And several supplement information was added in the revised manuscript.
4) What internal standard was applied?
Response: Thanks a lot for this kindly remind. The samples were extracted by acetonitrile, delipified by n-hexane, purified by neutral alumina column, analyzed by gas chromatography-electron capture detector, and quantified by external standard method.
5) Could you elaborate on the statement: “The establishment of pyrethroid residue method in aquatic products can not only improve the accuracy of analysis”?
Response: Thanks a lot for the carefully review on our manuscript. According to the reviewer’s suggestion, these sentences were rewritten and several relevant supplement information was also added in the revised manuscript, hope now it appeared better.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors aimed to simultaneously determine seven pyrethroid pesticide residues, of which four (cypermethrin, deltamethrin, fenvalerate, and permethrin) are the most frequently detected, in six aquatic products. All of investigated PYRs are widely distributed and have potential to cause adverse effects on biota. The proposed GC method resulted in high sensitivity and stability regarding the simultaneous determination of analyzed PYRs.
General comments
· In the Results and Discussion section, compare your findings with other methods used for the extraction and determination of analyzed PYRs.
Specific comments
- Lines 9-10: Unclear sentence. Please, rewrite it.
- Lines 16-17: Put this sentence before the previous one.
- Line 18: ″crucian″ is crucian carp?
- Line 18: ″litopenaeus vannamei″ was not well written. Replace with correct version ″Litopenaeus vannamei″ or even better ″Whiteleg shrimp″.
- Lines 26-28: Rewrite keywords. Some of them are already in the manuscript title.
- Lines 31-33: Specify which factors.
- Lines 41-42: Not clear. Anchor head eel and Chinese eel are parasites?
- Line 44: Replace ″fish surface parasites″ with external parasites of fish
- Lines 59-61: Provide the full names of PYRs you mention for the first time (eg. FEN, FLU, and CYH).
- Line 85: Indicate which aquatic products and provide their Latin names
- Lines 108-109: Replace ″Litopenaeus Vannamei″ with Whiteleg shrimp. Indicate also the number/amount of each aquatic product.
- Lines 215-217: Add reference(s).
Author Response
Dear Reviewer:
Thank you for your kind work to our manuscript (fishes-2856481). The manuscript has been revised carefully according to the reviewers’ valuable comments. The responses to the referees’ comments one by one are described as follows:
General comments
In the Results and Discussion section, compare your findings with other methods used for the extraction and determination of analyzed PYRs.
l Response: Thanks a lot for this kindly remind. We agree and therefore, the conclusion was rewritten and several relevant supplement information was also added in abstract.
Specific comments
1) Lines 9-10: Unclear sentence. Please, rewrite it.
l Response: Thanks. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better.
- Lines 16-17: Put this sentence before the previous one.
l Response: Thanks. We have made correction accordingly.
3) Line 18: ″crucian″ is crucian carp?
l Response: Thanks a lot for this kindly remind. ″crucian″ is crucian carp. And We have made correction accordingly.
4) Line 18: ″litopenaeus vannamei″ was not well written. Replace with correct version ″Litopenaeus vannamei″ or even better ″Whiteleg shrimp″.
l Response: Thanks a lot for this kindly remind. We have made correction accordingly.
5) Lines 26-28: Rewrite keywords. Some of them are already in the manuscript title.
l Response: Thanks a lot for this kindly remind. The keywords were rewritten accordingly, hope now it appeared better.
6) Lines 31-33: Specify which factors.
l Response: Thanks a lot. We have made correction accordingly.
7) Lines 41-42: Not clear. Anchor head eel and Chinese eel are parasites?
l Response: Thanks. Anchor head eel and Chinese eel are parasites. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better.
8) Line 44: Replace ″fish surface parasites″ with external parasites of fish.
l Response: Thanks. We have made correction accordingly.
9) Lines 59-61: Provide the full names of PYRs you mention for the first time (eg. FEN, FLU, and CYH).
l Response: Thanks. We have made correction accordingly.
10) Line 85: Indicate which aquatic products and provide their Latin names
l Response: Thanks. We have made correction according to the reviewers’ comments.
11) Lines 108-109: Replace ″Litopenaeus Vannamei″ with Whiteleg shrimp.
Indicate also the number/amount of each aquatic product.
l Response: Thanks a lot for this kindly remind. We have made correction accordingly and several supplement information was added in section 2.2.
12) Lines 215-217: Add reference(s).
l Response: Thanks a lot for this kindly remind. Several relevant literatures have been cited and added to the revised manuscript.
Reviewer 3 Report
Comments and Suggestions for AuthorsComments for author File: 
Comments.pdf
Author Response
Dear Reviewer:
Thank you for your kind work to our manuscript (fishes-2856481). The manuscript has been revised carefully according to the reviewers’ valuable comments. The responses to the referees’ comments one by one are described as follows:
General comment
There are published papers dealing with the same analytes and analytical methods as in the present manuscript, also within the matrices for aquatic organisms. A suggestion for the authors could be to discuss a little about available and used methods, compare them with the present one and emphasise (in the Abstract and Conclusions sections) the difference/importance of this extraction (and purification) method compared to others already available.
Response: Thanks a lot for this kindly remind. We agree and therefore, the conclusion was rewritten and several relevant supplement information was also added in abstract.
Specific comments
1) Line 18: Please write 'whiteleg shrimp' instead of 'Litopenaeus vannamei', or give the Latin names of all organisms mentioned here. See also lines 108, 241, 242, 250, 251, etc.
Response: Thanks a lot for this kindly suggestion. We have made correction accordingly.
2) Lines 30 and 37: Please check for typing errors.
Response: Thank. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better.
3) Lines 45 to 50: Please indicate the studied organisms.
Response: Thanks. We have made correction accordingly.
4) Lines 59 to 61: Why refer to the limits for fruit and vegetables (EC 396/2005) and not to Commission Regulation (EU) No 37/2010 of 22 December 2009 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin, Official Journal of the European Communities, L15 (2010)?
Response: Thanks a lot for this kindly suggestion. We have made correction accordingly, and the relevant reference was also replaced. (As reference 22)
5) Lines 67 and 68: To which country does this stetement refer as 'national', since international references were cited? In general, this statement is incorrect as there are many papers dealing with the detection of pyrethroids in aquatic products.
Response: Thanks a lot for this kindly suggestion. We have checked and rewritten these sentences accordingly. Several literatures dealing with the detection of pyrethroids in aquatic products were also cited in the revised manuscript.
6) Lines 69 to 71: Please write the names of the analytes consistently throughout the manuscript (see also lines 57 and 58).
Response: Thanks. We have made correction accordingly.
7) Lines 75 to 77: This statement and the reference are outdated, but do write something here to emphasise the importance of the present study.
Response: Thanks a lot for this kindly suggestion. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better.
8) Line 77: What was meant by 'establishment'?
Response: Thanks a lot for this kindly remind. We have checked and made correction accordingly in the revised manuscript.
9) Line 81: What was meant by 'domestic'?
Response: Thanks a lot for this kindly remind. We have checked and made correction accordingly.
10) Lines 81 and 82: What was meant by 'healthy development of aquaculture industry'?
Response: Thanks a lot for this kindly remind. We have checked and rewritten these sentences, hope now it appeared better.
11) Line 83: It would be more appropriate to use 'modified' instead of 'developed', as the GC method is very similar to that in: Sannino, Anna; Mirella, Bandini; Bolzoni, Luciana. (2003).
Response: Thanks. We have made correction accordingly.
12) Line 85: No risk assessment was performed in this study.
Response: Thanks. We have made correction accordingly.
13) Line 87: Please delete 'creation of a method' as this method already exists.
Response: Thanks. We have made correction accordingly.
14) Lines 83 to 89: Suggestion is to delete these lines from the manuscript as some parts are repeated from the previous text and some are misleading.
Response: Thanks a lot for this suggestion. We have deleted this section accordingly.
15) Line 94: Add 's' to 'formula'.
Response: Thanks. We have made correction accordingly.
16) Line 100: Note the manufacturer of the C18 columns.
Response: Thanks. The manufacturer of the C18 columns was added in the revised manuscript.
17) Line 101: SPE neutral alumina column was labelled as Cleanert in lines 14 and 131, but here only as Agela. Please label it as 'Cleanert, Agela' in Matherials and Methods section.
Response: Thanks. We have made correction accordingly.
18) Line 103: Please insert a space between 'ᶱC' and 'for'.
Response: Thanks. We have made correction accordingly.
19) Line 105: Please use the full names of the analytes in the headings of figures and tables throughout the manuscript and add essential information.
Response: Thanks. We checked the tables and figures, and the full names have been added accordingly.
20) Line 106: Please add 's' to 'formula'.
Response: Thanks. We have made correction accordingly.
21) Line 108: Why is the (incorrectly written) Latin name of only one species used?
Response: Thanks. We have made correction accordingly.
22) Line 117: Why is this text placed in 'Text S1' and not in sections 2.1 or 2.3?
Response: Thanks a lot for this good suggestion. We agree and therefore, the text was placed in section 2.1 in the revised manuscript
23) Line 119: Please write 'homogenized' instead of 'crushed'.
Response: Thanks. We have made correction accordingly.
24) Line 123: Please note the volume of supernatant transferred.
Response: The volume of supernatant transferred was noted in the revised manuscript accordingly.
25) Line 126: Did the authors mean 'solution' instead of 'solvent'?
Response: Thanks. We have made correction accordingly.
26) Line 130: Please delete 'time'.
Response: Thanks. We have made correction accordingly.
27) Line 131: Please note the volume of extract transferred?
Response: The volume of extract transferred was noted in the revised manuscript accordingly.
28) Line 140: Please refer to the original method used and modified.
Response: Thanks a lot for this kindly remind. We have made correction accordingly.
29) Lines 156 and 157: Please rephrase this sentence to make it clearer.
Response: Thanks a lot for this kindly remind. We checked and revised the manuscript carefully according to the reviewer’s comments, hope now it appeared better.
30) Lines 162 and 163: Please insert 'under the same conditions' between 'separated' and 'by HP- 35'.
Response: Thanks a lot. We have made correction accordingly.
31) Lines 164 and 165: Summarize these sentences and insert them as part of the sentence in lines 162 and 163.
Response: Thanks a lot. The sentences in Lines 164 and 165 were summarized and inserted in lines 162 and 163 accordingly.
32) Line 246: There is no legend explaining the abbreviations of the analytes' names and no explanation of what 'aquatic product' stands behind the letters A, B, C, D, E and F and what the superscript letters stand for.
Response: Thanks a lot for this kindly remind. We have made correction accordingly and several supplement information was added below Table 1.
33) Line 258: Delete 'were'.
Response: Thanks. We have made correction accordingly.
34) Lines 259 to 261: Please rephrase this sentence to make it clearer.
Response: Thanks. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better.
35) Line 262: Please move 'were' to stand between ’11.1%' and 'lower'.
Response: Thanks. We have made correction accordingly.
36) Line 263: Please explain in the text above this table why the RSD values for spike level 100 have been omitted from this table.
Response: Thanks a lot for this kindly remind. We checked and revised carefully according to the reviewer’s comments. Several supplement information was added in section 3.4.4.
37) Line 265: Write 'aquatic organisms' (or similar) instead of 'kinds of'; the same applies to line 273.
Response: Thanks. We have made correction accordingly.
38) Line 269: Write 'in' instead of 'of'.
Response: Thanks. We have made correction accordingly.
39) Line 270: Write 'crab' instead of 'carb' (same comment for line 272) and 'listed' instead of 'list'; why was not 'white shrimp' noted in this sentence to contain PER?
Response: Thanks. We checked and revised carefully according to the reviewer’s comments, hope now it appeared better. PER data of white shrimp was also added in the revised manuscript.
40) Lines 270 and 271: The statement of this sentence is not supported by Figure S3, as it shows chromatograms of PER in a scallop sample (a) and seven PYRs in standard solutions (b); however, this information can be found in Table S1.
Response: Thanks a lot for this kindly remind. We have made correction accordingly.
41) Line 271: Please delete 'of' and insert 'respectively' at the end of the sentence.
Response: Thanks. We have made correction accordingly.
42) Line 274: Indicate the values of these limits set by the US and the EU.
Response: Thanks. The values of these limits set by the US and the EU were added in the revised manuscript.
43) Lines 277: Note the full name of PYRs and its constituents in relation to this study.
Response: Thanks. We have provided the full name of PYRs and its constituents in relation to this study accordingly.
44) Line 278: The statement 'Compared with other separation techniques…' cannot stand, as it is not supported by corresponding text in this manuscript, since no other technique was mentioned and discussed here.
Response: Thanks. We have made correction and rewritten this section accordingly.
45) Line 286: Please reword 'easy popularized'.
Response: Thanks. 'easy popularized' was instead of 'easy operation' in the revised manuscript.
46) Lines 276 to 286: This section needs to be rewritten to emphasise the strengths of the present study and to rely on facts already mentioned in the manuscript.
Response: Thanks a lot for this kindly remind. We have rewritten this section accordingly, hope now it appeared better.
47) Line 297: Please format the references.
Response: Thanks a lot. The references have been formatted in the revised manuscript.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThank you for correcting the manuscript. I am satisfied and have no comments.
Best regards
Author Response
Dear Reviewer:
Thank you for your kind work to our manuscript (fishes-2856481). The responses tothe referees’ comments one by one are described as follows:
General comment: Quality of English Language
Response: Thanks a lot for this kindly remind. We checked the whole manuscript and revised the English language carefully according to the reviewer’s comments, hope now it appeared better.
Reviewer 3 Report
Comments and Suggestions for AuthorsComments for author File: Comments.pdf
The English language needs to be checked throughout the manuscript, as a few but important corrections are necessary.
Author Response
Dear Reviewer:
Thank you for your kind work to our manuscript (fishes-2856481). The language of the manuscript has been checked and optimized carefully, hope now it appeared better. The responses to the specific comments one by one are described as follows:
General comment: Quality of English Language
Response: Thanks a lot for this kindly remind. We checked the whole manuscript and revised the English language carefully according to the reviewer’s comments, hope now it appeared better.
Specific comments
1) The suggestion is to elaborate the strengths of this modified extraction and analysis methods by comparing those with one or two similar ones, in no more than ten lines.
Response: Thanks a lot for this kindly remind. We have checked and revised the conclusion accordingly, the modified extraction and analysis methods were compared with other similar methods as follows: Compared with previous findings (Sannino et al., 2003), a combination of acetonitrile and n-hexane saturated with acetonitrile rather than 40 mL acetone and 20 mL ethyl acetate–cyclohexane (50+50, v/v) was used for sample extraction, therefore, demonstrating the less solvent, and cost-effectiveness. The extracts were cleaned up on a Cleanert® Alumina N column rather than a Florisil cartridge, since it was more effective with an advantage of short cleanup period (Esteve-Turrillas et al., 2005).
2) Lines 1, 100, 117, 175, 180, etc.: small numbers from one to nine (ten) should be spelled out
Response: Thanks. We checked the whole manuscript and revised carefully according to the reviewer’s comments, hope now it appeared better.
3) Lines 13, 29, 30, etc.: check for correct capitalisation throughout the manuscript
Response: Thanks. We checked the whole manuscript and made correction carefully according to the reviewer’s comments, hope now it appeared better.
4) Line 28: change 'easy popularized' to 'easily accepted'
Response: Thanks. We have made correction accordingly.
5) Line 30: please delete 'to be as'
Response: Thanks. We have made correction accordingly.
6) Line 34: change 'nutrient' to 'nutrients'
Response: Thanks a lot. We have made correction accordingly.
7) Line 35: change 'of' to 'from'
Response: Thanks. We have made correction accordingly.
8) Line 36: change 'problems' to problem'
Response: Thanks. We have made correction accordingly.
9) Line 38: change 'abuse' to 'misuse'
Response: Thanks. We have made correction accordingly.
10) Line 41: change 'pesticides' to 'pesticide'
Response: Thanks. We have made correction accordingly.
11) Line 42: change 'usage' to 'use'
Response: Thanks. We have made correction accordingly.
12) Line 47 change 'when' to 'if'
Response: Thanks. We have made correction accordingly.
13) Line 48 delete 'with'
Response: Thanks. We have made correction accordingly.
14) Line 51: missing 'to' after 'exposure'
Response: Thanks. We have made correction accordingly.
15) Line 50: add '.' after 'al'
Response: Thanks. We have made correction accordingly.
16) Line 57: delete 's' in ' pyrethroids'
Response: Thanks. We have made correction accordingly.
17) Lines 57 to 60: please be careful when to use the plural and when to use the singular in 'pyrethroids residues', 'Residues of pesticide'; and also 'PYRs residues' in line 86
Response: Thanks. We checked the whole manuscript and revised carefully according to the reviewer’s comments, hope now it appeared better.
18) Line 86: change 'wide coverage' to 'comprehensive'; 'easy popularized' to 'easily accepted' 'detecting PYRs' to ' detection of PYR'
Response: Thanks a lot for this kindly suggestion. We have made correction accordingly.
19) Line 87: please rephrase or delete 'to expand the application of more PYRs' as it makes no sense; change 'standards' to 'standard methods'
Response: Thanks a lot for this kindly suggestion. We have made correction accordingly.
20) Line 100: change 'were' to 'are'
Response: Thanks. We have made correction accordingly.
21) Line 113: change 'balance' to 'equilibrium'
Response: Thanks. We have made correction accordingly.
22) Line 131: please delete '(Text S1)' here and the corresponding text in the supplementary material
Response: Thanks. We have made correction accordingly.
23) Lines 158 to 163: I assume that the authors did not develop this method themselves (it is very similar to that of Sannino et al., 2003). Therefore, please provide the reference for the (modified) method used here.
Response: Thanks a lot for this kindly suggestion. The relevant references have been cited accordingly in the revised manuscript.
24) Line 180: change ' standards solution' to ' standard solutions'
Response: Thanks. We have made correction accordingly.
25) Lines 253, 261 and 283: please write the names of the organisms consistently throughout the manuscript; check the entire manuscript
Response: Thanks. We checked the whole manuscript and revised carefully according to the reviewer’s comments, hope now it appeared better.
26) Line 282: insert 'and' after ' 11.1%'
Response: Thanks. We have made correction accordingly.
27) Line 291: delete 'of' and write 'in concentrations' instead; insert 'respectively' before '(Fig. S3…'
Response: Thanks. We have made correction accordingly.
