Simultaneous Determination of Vitamin E and Vitamin K in Food Supplements Using Adsorptive Stripping Square-Wave Voltammetry at Glassy Carbon Electrode
, Blanka Švecová 3, Tahir Arbneshi 2, Radovan Metelka 3, Zuzana Bílková 1 and Lucie Korecká 1,*
Round 1
Reviewer 1 Report
The simultaneous determination of vitamin E (a-TOH) and vitamin K (VK1) by using AdSV coupled with SWV detection was described. The experimental parameters of both steps (AdSV and SWV) were optimized and the main analytical parameters (linear range, RSD, LOD, and LOQ) for VK1 and a-TOH were reported. The new method was applied to analyze commercial food supplements.
However, before publication some issues should be carefully considered:
(i) Essential aspects exposed in sections 3.2.3 and 3.3 (lines 259-262) are presented rather confusing. Please, reformulate them.
(ii) Experimental data showing the recovery for synthetic samples or/and VK1 & a-TOH determinations in plasma will be relevant concerning the method performances.
(iii) The manuscript should be thoroughly checked to eliminate typing/language errors as well as to improve its clarity/quality.
Author Response
(i) Essential aspects exposed in sections 3.2.3 and 3.3 (lines 259-262) are presented rather confusing. Please, reformulate them.
Answer: This part was reformulated to be clearer for potential readers.
(ii) Experimental data showing the recovery for synthetic samples or/and VK1 & a-TOH determinations in plasma will be relevant concerning the method performances.
Answer: Due to low LOQ values, it could be considered that the developed electroanalytical method could find its application in the analysis of plasma samples, especially if you take account of the concentration levels of these lipophilic vitamins. Moreover, in Reference 26, the determination of VK1 in human plasma using AdSV at the carbon paste electrode has been already done.
(iii) The manuscript should be thoroughly checked to eliminate typing/language errors as well as to improve its clarity/quality.
Answer: Thank you for your suggestion to improve the English language. The manuscript was revised by editing service.
Reviewer 2 Report
Very interesting topic. Excellent work for electroanalytical chemistry. In my point of view, this manuscript can be accepted in the present form.
Author Response
(i) Extensive editing of English language and style required.
Answer: As it was already mentioned, the manuscript was revised by editing service.
Reviewer 3 Report
The reviewed manuscript has been well designed with good theoretical and practical background. The methods have been described very carefully and the results have been very clearly.
The new voltammometric method is a very great importance from the practical point of view and can be successfully used in quality control in food as well as in pharmaceutical industry. Unfortunately I am afraid that short linearity range may limit use of this method.
I have also sugestion for authors to try develop similar method for real food samples e.g. oils.
Author Response
(i) The new voltammometric method is a very great importance from the practical point of view and can be successfully used in quality control in food as well as in pharmaceutical industry. Unfortunately I am afraid that short linearity range may limit use of this method.
Answer: We would like to thank the reviewer for a positive evaluation. Although we are aware of a relatively narrow linear range, the sample preparation could be adapted to this. On the other hand, we find a great benefit in the simultaneous detection of both vitamins.
(ii) I have also sugestion for authors to try develop similar method for real food samples e.g. oils.
Answer: thank you for your suggestion. Previous publications suggest that this could be possible (Ref. 1,2).
Round 2
Reviewer 1 Report
The revised form of the manuscript incudes acceptable changes related to all my comments. Consequently, I agree with the publication of its actual variant.
