PONE-D-24-18964Lead acetate–based test strip method for rapid and quantitative detection of residual sulfur dioxide in Chinese herbal medicinesPLOS ONE

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PLOS ONE

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 [This work was supported by the Key R&D plan of Shaanxi Province (No.2021ZDLSF01-07), Shaanxi provincial People's Hospital Science and Technology Personnel Support Program(No.2021LJ-02), Key Research and development program of Shaanxi Province(No.2022KWZ-20), Shaanxi provincial People's Hospital Science and Technology Development Incubation Fund（2023YJ-22）Key Research and development program of Shaanxi Province（2024SF-YBXM-081）].  

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Partly

Reviewer #4: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: N/A

Reviewer #4: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: No

Reviewer #4: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: No

Reviewer #4: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: In this work, the authors introduce lead acetate–based test strip method for rapid and quantitative detection of residual sulfur dioxide in Chinese herbal medicines. The content is detailed and enriching, showcasing the authors' broad perspective. However, there are several issues within the article that require some modifications：

1. Please reorganize the abstract part. Background, Methods, Results and Conclusions should not be indicated.

2. Please rewrite the keyword ‘Quantitative’.

3. The section 2. Materials and methods need to be reorganized. There are too many subtitles which make experimental details unclear.

4. Please reorganize the results part by reducing subtitles and extract the main results followed by significant biological explication.

5. Please add scale in Figure 1.

6. Please add error bar in the experimental curves.

7. The figutes are not good presented.

8. The table 2 is not good enough.

In conclusion, the author shows enough expermental details and results to support the main idea. However, the work needs to be slightly improved. I recommend the publication after a major revision.

Reviewer #2: In section 3.2. Preparation of standard grayscale cards, teststrips with a lead acetate concentration of 15% were prepared. However, in section 3.1.2.1. and Figure 2a, lead acetate with concentration of 20% showed better linear pattern of the detected gray value.

In section 3.4.2.1. Precision testing, SO2 residual concentration for the three herbs was not clearly addressed in the method part.

The colors of the line on Figure 2a can’t correspond to the caption beside it.

Reviewer #3: In this manuscript, entitled “Lead acetate–based test strip method for rapid and quantitative detection of residual sulfur dioxide in Chinese herbal medicines”, the authors developed a rapid and quantitative sulfur dioxide detection technique for the evaluation of sulfur dioxide residues in Chinese herbal medicines. The authors converted the sulfur dioxide to hydrogen sulfide, which was then detected using lead acetate test paper. My questions and suggestions are as follows:

1. In “Introduction” section:

Why don't you refer to the latest edition of Chinese Pharmacopoeia (2020)?

In addition to the mentioned common detection methods in addition to acid-base titration, ion chromatography, gas chromatography, fluorescence derivatization, colorimetry, etc., there are also many methods for the rapid detection of sulfur dioxide residue in Chinese herbal medicine. Please provide an overview of the latest research to highlight the need for the detection methods in this study.

2. In “Methods” section:

Please attach the chemical reaction formula.

What was the reason for choosing sodium borohydride (NaBH₄) as the reducing agent? The reaction between sulfur dioxide or sulfite and sodium borohydride is not a common chemical reaction because their chemical properties do not directly promote such reactions under normal conditions. However, under certain conditions, the two compounds may react, but this is rare and the reaction conditions are usually harsh. What reaction conditions were used in this study to facilitate the reaction? This point is not seen in the article at present!

Why not use real Chinese medicine for research? In this study, what is the role of Chinese herbal medicine extract in it? Is it just a simulation? The real detection method will carry out pre-extraction treatment of Chinese medicinal materials, and the pre-treatment steps will also affect the reaction conditions. Therefore, the use of Chinese medicinal materials for real detection is an essential part of the establishment of the new methodology!

It is suggested that a batch of Chinese medicinal materials should be simultaneously tested by other known mature methods, such as acid-base titration in Chinese Pharmacopoeia, in order to demonstrate the accuracy of the detection results of this method.

3. In “3.1.1”:

In this part, the best reaction time was determined to be 10 min. Why was 15 min used in 3.1.2.1. to detect the influence of different concentrations of lead acetate on the detection accuracy?

4. In “3.1.2.1”:

In this part, CN95 membrane was used to detect the influence of different concentrations of lead acetate on the detection accuracy. However, the best experimental membrane type was determined as CN 140 in 3.1.2.2. Please explain the different membrane types of the two parts!

Should the optimal membrane type be determined first, and then the influence of the concentration of lead acetate under the optimal membrane type on the detection results be tested?

5. In “Discussion” section:

There is no discussion section in this paper. Please supplement the latest progress of relevant technology in the current research field, compare it with this study, and discuss the limitations and future research direction of this technology!

Reviewer #4: The paper has established a rapid detection technique utilizing lead acetate test strips for the prompt identification of SO2 in traditional Chinese medicinal materials and herbal preparations. The idea is interesting and data is fine. I Just have two questions.

1. Why the membrane type has effect on detection accuracy? The authors should address it in the context.

2. The language need to be improved and polished.

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Reviewer #1: No

Reviewer #2: Yes: HSU, SHUO-MIN

Reviewer #3: No

Reviewer #4: No

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Lead acetate–based test strip method for rapid and quantitative detection of residual sulfur dioxide in Chinese herbal medicines

PONE-D-24-18964R1

Dear Dr. Zhao,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Tien Anh Tran

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

After reviewing carefully your revised paper and the recommendations of reviewers, the current manuscript could be accepted to publish on Plos One.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #4: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

Reviewer #4: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #4: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

Reviewer #4: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #4: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

Reviewer #4: As for the revision, I think all my questions are answered and I think the manuscript is acceptable now.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

Reviewer #4: No

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