Articles | Volume 3, issue 2
© Author(s) 2022. This work is distributed underthe Creative Commons Attribution 4.0 License.
Fine optimization of a dissolution dynamic nuclear polarization experimental setting for 13C NMR of metabolic samples
- Final revised paper (published on 29 Sep 2022)
- Preprint (discussion started on 15 Jul 2022)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
- RC1: 'Comment on mr-2022-14', Anonymous Referee #1, 20 Jul 2022
RC2: 'Comment on mr-2022-14', Benno Meier, 26 Jul 2022
- EC1: 'Reply on RC2', Geoffrey Bodenhausen, 26 Jul 2022
- EC2: 'Reply on RC2', Geoffrey Bodenhausen, 26 Jul 2022
- AC1: 'Response to reviewers comments mr-2022-14', Patrick Giraudeau, 30 Aug 2022
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision
AR by Patrick Giraudeau on behalf of the Authors (13 Sep 2022)  Author's response Author's tracked changes Manuscript
ED: Publish as is (16 Sep 2022) by Geoffrey Bodenhausen
AA: Author's adjustment | EA: Editor approval
AA by Patrick Giraudeau on behalf of the Authors (28 Sep 2022) Author's adjustment Manuscript
EA: Adjustments approved (29 Sep 2022) by Geoffrey Bodenhausen
The manuscript submitted to Magnetic Resonance by Dey et al. represents a valuable piece of work that with some work on the manuscript will serve a good basis for development of robust workflow for metabolomic studies, will allow other laboratories to get started with dDNP-NMR based metabolomics and will provide a data basis for cross laboratory studies with different hyperpolarization methods.
I am very impressed with the systematic and voluminous work gone into the manuscript.
I do however find that the manuscript is written a bit hasty and that the value of the presented improvements could be enhanced by sorting out some of the more spurious findings and supporting other findings with additional data and reasoning as well as discussion. I will below suggest the most pressing things to work with and at the same time declare that I at this stage did not go into details.
Also, in the solid-state figures I do not understand how to interpret the “thermal signal” (in fig.3a I guess it is as in fig4.a the 1H signal without microwaves on. But how can this signal be on the same scale as the 1H DNP signal? In that case it looks as though the polarization is very low.
Make sure to give all the important information in the figure legends eg. tempol concentration in figure 4.
p.8 section on “B.4 Vitrification parameters”:
It is natural when working with complicated methods that experimental routines are implemented that has little theoretical meaning. Several points in this section refer to such experimental routines based on non-investigated observations. If rate of vitrification is important it should be shown. If it matters in which order the metabolites are dissolved (water first or water:glycerol mix or glycerol) it is a matter of solubility and should be investigated. Then also sample temperature may be an issue as well as total dissolution volume. I suggest you separate out parameters that you have identified as possibly important for later study/optimization from the parameters that you have investigated and can conclude on and discuss.
The discussion is generally kept to stating the findings with a comment. The results are rarely discussed.
The authors have previously published (also nicely referenced in the manuscript) significant contributions to the use of dDNP NMR for allowing 13C direct detect natural abundance mixture analysis. Significant findings in those reports are not discussed relative to the results presented in this manuscript (e.g. use of Hellmanex and a suited internal standard for quantification). Please discuss the alternative choices in this manuscript and how they have improved previous results or was not part of the purpose.
The results are summarized stating that the main contribution to the significant method improvement is the transfer time. It would be interesting with a discussion about the consequences of the improvements. Especially the important choice of dissolving in methanol could be strengthen with a discussion on chemical shift changes in methanol (lack of database, temperature and concentration influences).
I just noticed:
Spelling error in Figure 1: ‘magentic’ should be ‘magnetic’
Example of unprecise language: l.148 ‘to trace the amount’ - maybe to weigh?
Please explain how the factor 2900 difference in sensitivity between 13C and 1H is calculated