Protoporphyrin IX Based All-Solid-State Ion-Selective Electrodes for Choline Determination In Vitro

Round 1

Reviewer 1 Report

The paper by Wang et al.have reported Protoporphyrin IX based solid state ISE for choline detection. Reported ISE have high selectivity, sensitivity in physiological range and stability in different conditions (pH and temperature). Present paper is very undastandable and nicely written. An importance of choline detection is well explained by the author and backed up by numerous references. The working principle and interest of solid-state ISEs for choline detection are well explained. Preparation of Ch ISEs is thoroughly explained. Conditions of each experiment were well explained. pH, temperature influence, reputability, reproducibility and stability studies were very convincing and properly designed.

Authors have mentioned the millimols level concentration of choline in a human body (28), haven’t given any precise values, that could help to understand the ranges.

Here are some other minor changes to be made when the evaluation is given:

(56) showed excellent sensitivities and low detection limits… - the numbers could be given to understand the level of excellence

(52) ions were not yet satisfactory…- the precision needs to be made

(89) fast response time… -the number needs to be given

(127) It is important to explain the conditioning step…- why it is necessary and why the concentration of 0.01 mM was chosen.

(176) … these ions could be neglected… - dynamic response curve upon interfering analytes addition could be added to further prove the point

(197) 34-42 °C are almost same… - maximum deviation (in %) should be given

Overall the paper deserves to be accepted Applied Sciences with very minor corrections.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Authors present a method of obtaining choline-selective ion-selective electrodes using protoporphyrin IX as an ionophore.

Recommends rejecting the publication due to the fact that there are basic shortcomings in the field of chemistry (The tests were carried out in an acetate buffer at pH (7-8) when the pKa of the buffer was 4.8). .

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Very interesting work of high scientific quality. My only remark concerns the lack of comparison of the obtained results with others published so far in the literature. 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

The research presented in this manuscript is important and will be useful to the chemical sensing community. The methods used are sufficiently clarified and experiments are designed well.

The only my concern regarding presented publication is the omission the ammonium ion in the selectivity determination experiment. The ammonium ion is present in biological systems and also in cerebrospinal fluid. I will be glad do get the explanation why authors decided to omit the ammonium ion in presented studies (in the cited literature e.g. [39] the NH4+ ion was taken into consideration).

Author Response

Please see the attachment

Author Response File: Author Response.pdf