Miniaturized Solid Phase Extraction Techniques Applied to Natural Products

Round 1

Reviewer 1 Report

The present paper describes a review of some miniaturized solid-phase extraction techniques which is applied to natural products. The paper is interesting, however, improvements would be valuable.

- the title of section No. 2, should be reorganized as this is a review paper. I don't see any "materials and methods" in this part.

- the third row from the bottom of Table 1 - Shouldn't be presented two values for the thickness of sorbent? As the SPME fiber consists of several materials (DVB/CWR/PDMS). Now it is written only 120 micrometers.

- line 199 - explain "CG"

- Latin names must be in italic in the reference list.

- I would recommend adding a table comparing all methods described. comparison can be done by several aspects such as type of analytes (volatile, non-volatile, or both), amount of the sample (for example from XX micrograms to YY grams), duration of the extraction, sorbents, which special equipment is necessary after extraction, advantages, disadvantages, and so on. 

Author Response

We thank the comments and suggestions posed by the Reviewers.

On the following sentences you may find the detailed responses to reviewers 1 comments and concerns. We highly appreciate the detailed valuable comments and believe that the interest and scientific quality of the manuscript improved substantially. This reviewer’s suggestions are highlighted in yellow and with track changes.

The present paper describes a review of some miniaturized solid-phase extraction techniques which is applied to natural products. The paper is interesting, however, improvements would be valuable.

- the title of section No. 2, should be reorganized as this is a review paper. I don't see any "materials and methods" in this part.

Response: The authors included search engines, keywords and inclusion criteria in the materials and methods section as this is common in some reviews. This section was reorganized. The title of the material and methods section was eliminated as suggested.

- the third row from the bottom of Table 1 - Shouldn't be presented two values for the thickness of sorbent? As the SPME fiber consists of several materials (DVB/CWR/PDMS). Now it is written only 120 micrometers.

Response: Thank you for the observation. Information about the thickness of the sorbent was added according the information that appears in the manuscript by Jagatić Korenika et al.

- line 199 - explain "CG"

Response: Thank you for the observation. This was a typing error CG is GC (gas chromatography).

- Latin names must be in italic in the reference list.

Response: The reference list was made using the Mendeley software. The information about each reference is in accordance to the publisher’s stytle. We have manually italicized all Latin names in the reference list.

- I would recommend adding a table comparing all methods described. comparison can be done by several aspects such as type of analytes (volatile, non-volatile, or both), amount of the sample (for example from XX micrograms to YY grams), duration of the extraction, sorbents, which special equipment is necessary after extraction, advantages, disadvantages, and so on. 

Response: Thank you very much for your observation. The main characteristics and a comparison of the techniques (SPME, SBSE and MEPS) are described in Table 3. It is difficult to make further comparisons, since the remaining techniques have unique and different characteristics (eg. MIPS, MSPD and µ-SPE), which impairs this task. The amount of sample depends on the sensitivity and the limits of detection and quantification that the authors want to achieve, and not the extraction technique used. Concerning the type of compound (volatile, non-volatile or both), since these techniques allow the determination of all types of compounds (eg MEPS, headspace SPME or direct immersion SPME) this type of categorization would not bring useful information to the reader. The type of sorbents depends on the technique used, since most authors use commercial sorbents available for each technique (eg MEPS or SPME). All these methods can be easily applied to LC or GC, and the choice will depend mainly on the compounds that are intended to be detected. Regarding the duration of the extraction process, most of the authors do not describe it for techniques other than SPME. This parameter is important for SPME and this information appears in the conditions column (Table 1).

We regret that we cannot include more information on the comparison of these techniques. We hope the reviewer understands this situation.

Thank you for your comments and suggestions!

Reviewer 2 Report

 

The article submitted for review entitled "Miniaturized solid phase extraction techniques applied to natural products" is a critical review of microextraction techniques used to isolate or evaluate active ingredients from natural materials.

I read the study with great interest because these techniques are gaining popularity due to their advantages related to the low consumption of organic solvents and the small amount of sample used in relation to more classic sample preparation techniques. Their use in extracting compounds from natural products is still limited.

The article is prepared in accordance with the art of preparing review manuscripts, methodologically and descriptively it does not raise objections.

The cited literature is relevant to the topic.

A few thoughts came to mind while reading:

1. There are 4 self-citations of Gallardo E. in the study. I understand that these are important works, but please reduce it to a maximum of 2 works.

2. In the part materials and methods, the authors write about a small number of centers and research groups using these techniques. According to the reviewer, this is not entirely true. One of such centers, but not indicated by the authors of the study, is e.g. team of prof. Stuper-Szablewska K. from the Chemistry Department of the Poznań University of Life Sciences. It is worth that the authors get acquainted with selected studies that concern the chemistry of natural products in various contexts. Please complete the study with the indicated aspects of extraction, e.g. mycotoxins.

a) Stuper-Szablewska K., Szablewski T., Buśko M., Perkowski J. 2016. Changes in contents of trichothecenes during commercial grain milling. LWT-Food Science and Technology. 69, 55-58.

b) Przybylska-Balcerek A., Szablewski T., Cegielska-Radziejewska R., Góral T., Kurasiak-Popowska D., Stuper-Szablewska K. 2022. Assessment of Antimicrobial Properties of Phenolic Acid Extracts from Grain Infected with Fungi from the Fusarium genus. Molecules. 27, 1741.

c) Szablewski T., Stuper-szablewska K., Cegielska-Radziejewska R., Tomczyk L., Szwajkowska-Michałek L., Nowaczewski S. 2022. Animals. Comprehensive Assessment of Environmental Pollution in a Poultry Farm Depending on the Season and the Laying Hen Breeding System. 12, 740.

Author Response

We thank the comments and suggestions posed by the Reviewers.

On the following sentences you may find the detailed responses to reviewers 2 comments and concerns. We highly appreciate the detailed valuable comments and believe that the interest and scientific quality of the manuscript improved substantially. This reviewer’s suggestions are highlighted in blue and with track changes.

The article submitted for review entitled "Miniaturized solid phase extraction techniques applied to natural products" is a critical review of microextraction techniques used to isolate or evaluate active ingredients from natural materials.

I read the study with great interest because these techniques are gaining popularity due to their advantages related to the low consumption of organic solvents and the small amount of sample used in relation to more classic sample preparation techniques. Their use in extracting compounds from natural products is still limited.

The article is prepared in accordance with the art of preparing review manuscripts, methodologically and descriptively it does not raise objections.

The cited literature is relevant to the topic.

A few thoughts came to mind while reading:

1. There are 4 self-citations of Gallardo E. in the study. I understand that these are important works, but please reduce it to a maximum of 2 works.

Response: Our intention in mentioning 4 publications was not self-citation. In fact, the authors have several publications since 2006 on miniaturized techniques, mainly SPME and MEPS with different applications. We think that 4 citations out of 128 references is an extremely low number. The references (3, 12, and the former 13 and 51) were chosen precisely because they describe characteristics of the techniques, advantages, drawbacks, etc. that are presented in this manuscript. We believe that it is important to place this information, once they have experience in their research work and routine analysis with these techniques. Three of these references are review articles (reference 3 is about miniaturized techniques in general, reference 12 is about headspace-SPME, and former reference 51 is about MEPS). We have removed the reference dealing with an application example (former reference 13).

2. In the part materials and methods, the authors write about a small number of centers and research groups using these techniques. According to the reviewer, this is not entirely true. One of such centers, but not indicated by the authors of the study, is e.g. team of prof. Stuper-Szablewska K. from the Chemistry Department of the Poznań University of Life Sciences. It is worth that the authors get acquainted with selected studies that concern the chemistry of natural products in various contexts. Please complete the study with the indicated aspects of extraction, e.g. mycotoxins.
3. a) Stuper-Szablewska K., Szablewski T., Buśko M., Perkowski J. 2016. Changes in contents of trichothecenes during commercial grain milling. LWT-Food Science and Technology. 69, 55-58.
4. b) Przybylska-Balcerek A., Szablewski T., Cegielska-Radziejewska R., Góral T., Kurasiak-Popowska D., Stuper-Szablewska K. 2022. Assessment of Antimicrobial Properties of Phenolic Acid Extracts from Grain Infected with Fungi from the Fusarium genus.  27, 1741.
5. c) Szablewski T., Stuper-szablewska K., Cegielska-Radziejewska R., Tomczyk L., Szwajkowska-Michałek L., Nowaczewski S. 2022.  Comprehensive Assessment of Environmental Pollution in a Poultry Farm Depending on the Season and the Laying Hen Breeding System. 12, 740.

Response: Thank you very much for the observation and for providing the references. Undoubtedly, the group of Prof. Stuper-Szablewska is well known by the scientific community in the use of microextraction techniques. These references were not included in the review because they could not be found by the search engines with the search strings that were used, namely “natural products”. Despite being requested by the reviewer, we have not been able to include these references since the reference (LWT-Food Science and Technology 2016; 69, 55-58) does not describe any miniaturized technique and the same happens with this one: Molecules 2022; 27, 1741. Regarding the reference (Animals 2022;12(6):740), the authors detect volatile compounds in house dust samples and not in natural products.

Thank you for your comments and suggestions!

 

Round 2

Reviewer 2 Report

Dear Authors, I accept your explanations, however, my intention was to indicate that the topic has not been sufficiently exhausted. The explanations regarding the indicated publications may be correct, but it was an indication to find in the output such items that would be suitable for citation. I regret to note that the Authors did not, or did not wish to, provide a comprehensive review.

 

Detailed notes:

1. Please correct the entire text for the English language used.

2. Please correct the punctuation marks used throughout the study. In the summary itself, additional dashes appear, e.g. in lines 680, 685, 686 and many others.

3. Please explain in detail what this article contributes to world science. The fact that microextraction techniques have their advantages over traditional - large-volume is already known. Maybe it is worth slightly modifying the purpose of the study and clearly showing the advantages and disadvantages in the table in relation to the goal.

Author Response

This reviewer’s suggestions are highlighted in yellow.

 

Comments and Suggestions for Authors

Detailed notes:

1. Please correct the entire text for the English language used.

Response: Thank you for the observation. The manuscript was revised (we have used the option “track changes” of MS Word to to mark the changes).

2. Please correct the punctuation marks used throughout the study. In the summary itself, additional dashes appear, e.g. in lines 680, 685, 686 and many others.

Response: Thank you for the observation. The manuscript was revised.

3. Please explain in detail what this article contributes to world science. The fact that microextraction techniques have their advantages over traditional - large-volume is already known. Maybe it is worth slightly modifying the purpose of the study and clearly showing the advantages and disadvantages in the table in relation to the goal.

Response: This manuscript intends to review the most used solid-based microextraction miniaturized sample preparation techniques applied to the determination of natural products. The main applications of these methodologies were discussed, with special focus on natural products analysis, as well as their advantages and disadvantages over the traditionally used sample preparation techniques. Up to date no work has been published with full dedication on solid microextraction procedures applied to natural products. From our perspective, and once we work in the laboratory routine with these products, we have tried to carry out a critical and useful review for all scientists working in the natural products field. We are not sure that we have understood properly what the reviewer means, but the main advantages and drawbacks of each technique appeared in the text and now also in Table 3.

Thank you for your comments and suggestions!