Simultaneous Electrochemical Sensing of Dopamine, Ascorbic Acid, and Uric Acid Using Nitrogen-Doped Graphene Sheet-Modified Glassy Carbon Electrode

Round 1

Reviewer 1 Report

In this work, the author reported sensor for determination of DA.  The sensor could successfully determine the DA in the co-existence of UA and AA. The practical applicability of as-developed N-GSs/GCE sensor was verified by sensing the study analytes in real specimens, with satisfactory recovery rates. The resulted reported in the work is suitable for publication. However, few discussions needs improvement.

1. In the introduction, the author should provide more concrete view on the type of materials exists for DA determination and their performance. One table with important set of materials reported so far would be beneficial./

2. In the PXRD, the sharp peak around 30 2theta is not explained in the paper.

3. Better to determine the surface of the materials and corelate to the sensing.

4. The mechansim of sensing is not clear.

It will be great if author provide more information on the points.

Thanks

Author Response

Comments and Suggestions for Authors

In this work, the author reported sensor for determination of DA.  The sensor could successfully determine the DA in the co-existence of UA and AA. The practical applicability of as-developed N-GSs/GCE sensor was verified by sensing the study analytes in real specimens, with satisfactory recovery rates. The resulted reported in the work is suitable for publication. However, few discussions needs improvement.

1. In the introduction, the author should provide more concrete view on the type of materials exists for DA determination and their performance. One table with important set of materials reported so far would be beneficial.

Dear reviewer, we added the comparative table in the manuscript.

2. In the PXRD, the sharp peak around 30 2theta is not explained in the paper.

Dear reviewer, this peak is not one of the index peaks in the prepared sample. This peak can be noise or related to impurity.

3. Better to determine the surface of the materials and corelate to the sensing.

Dear reviewer, we added the surface area of the modified electrode in the manuscript.

4. The mechansim of sensing is not clear.

Dear reviewer, we added the redox mechanism of dopamine in the manuscript.

Reviewer 2 Report

This manuscript describes the synthesis of N-doped graphene and its applications for dopamine sensing. The concept is interesting and the results are clear. However, some points should be addressed.

1. In the introduction, the full names of UA, and AA should be written.

2. Some examples and references on the sensing performance of nanomaterials should be added in the introduction.

3. Authors explained that the well-dispersed suspension of N-GSs was drop-coated on GCE. How was reduced graphene well-dispersed?

4. N-doping extents are an important factor. Authors should give the N content in N-GSs.

Author Response

Comments and Suggestions for Authors

This manuscript describes the synthesis of N-doped graphene and its applications for dopamine sensing. The concept is interesting and the results are clear. However, some points should be addressed.

1. In the introduction, the full names of UA, and AA should be written.

Dear reviewer, we added the full names of UA and AA in the introduction section.

2. Some examples and references on the sensing performance of nanomaterials should be added in the introduction.

Dear reviewer, we added the comparative table in the manuscript.

3. Authors explained that the well-dispersed suspension of N-GSs was drop-coated on GCE. How was reduced graphene well-dispersed?

Dear reviewer, we corrected it.

4. N-doping extents are an important factor. Authors should give the N content in N-GSs.

Dear reviewer, we added the EDS spectrum in the manuscript.

Round 2

Reviewer 2 Report

The authors addressed the reviewer's comments. So I agree to the publication of the manuscript.