Vanillin isotopic intramolecular 13C profile through polarization transfer NMR pulse sequence and statistical modelling

Dissolution-dynamic nuclear polarization can be boosted by employing multiplecontact cross-polarization techniques to transfer polarization from 1H to 13C spins. The method is efficient and significantly reduces polarization build-up times, however, it involves high-power radiofrequency pulses in a superfluid helium environment which limit its implementation and applicability and prevent a significant scaling-up of the sample size. We propose to overcome this limitation by a stepwise transfer of polarization using a lowenergy and low-peak power radiofrequency pulse sequence where the 1H®13C polarization transfer is mediated by a dipolar spin order reservoir. An experimental demonstration is presented for [1-13C]sodium acetate. A solid-state 13C polarization of ~43.5% was achieved using this method with a build-up time constant of ~5.1 minutes, leading to a ~28.5% 13C polarization in the liquidstate after sample dissolution. The low-power multiple-step polarization transfer efficiency with respect to the most advanced and highest-power multiple-contact cross-polarization approach was found to be ~0.69.

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Boosting Dissolution-Dynamic Nuclear Polarization by Multiple-Step Dipolar Order Mediated 1H->13C Cross-Polarization

10.26434/chemrxiv.14377046.v1 ◽

2021 ◽

Author(s):

Stuart J. Elliott ◽

Olivier Cala ◽

Quentin Chappuis ◽

Samuel Cousin ◽

Morgan Ceillier ◽

...

Keyword(s):

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Pulse Sequence ◽

Polarization Transfer ◽

Cross Polarization ◽

Spin Order ◽

Sample Dissolution ◽

Dipolar Order ◽

Multiple Step ◽

Dissolution Dynamic Nuclear Polarization

Dissolution-dynamic nuclear polarization can be boosted by employing multiplecontact cross-polarization techniques to transfer polarization from 1H to 13C spins. The method is efficient and significantly reduces polarization build-up times, however, it involves high-power radiofrequency pulses in a superfluid helium environment which limit its implementation and applicability and prevent a significant scaling-up of the sample size. We propose to overcome this limitation by a stepwise transfer of polarization using a lowenergy and low-peak power radiofrequency pulse sequence where the 1H®13C polarization transfer is mediated by a dipolar spin order reservoir. An experimental demonstration is presented for [1-13C]sodium acetate. A solid-state 13C polarization of ~43.5% was achieved using this method with a build-up time constant of ~5.1 minutes, leading to a ~28.5% 13C polarization in the liquidstate after sample dissolution. The low-power multiple-step polarization transfer efficiency with respect to the most advanced and highest-power multiple-contact cross-polarization approach was found to be ~0.69.

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PHIP hyperpolarized [1-13C]pyruvate and [1-13C]acetate esters via PH-INEPT polarization transfer monitored by 13C NMR and MRI

Scientific Reports ◽

10.1038/s41598-021-85136-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alexandra Svyatova ◽

Vitaly P. Kozinenko ◽

Nikita V. Chukanov ◽

Dudari B. Burueva ◽

Eduard Y. Chekmenev ◽

...

Keyword(s):

Pulse Sequence ◽

Pulse Sequences ◽

Polarization Transfer ◽

Field Variation ◽

Biologically Relevant ◽

Field Cycling ◽

Thermal Polarization ◽

Nmr Signal Enhancement ◽

C Nmr

AbstractParahydrogen-induced polarization of 13C nuclei by side-arm hydrogenation (PHIP-SAH) for [1-13C]acetate and [1-13C]pyruvate esters with application of PH-INEPT-type pulse sequences for 1H to 13C polarization transfer is reported, and its efficiency is compared with that of polarization transfer based on magnetic field cycling (MFC). The pulse-sequence transfer approach may have its merits in some applications because the entire hyperpolarization procedure is implemented directly in an NMR or MRI instrument, whereas MFC requires a controlled field variation at low magnetic fields. Optimization of the PH-INEPT-type transfer sequences resulted in 13C polarization values of 0.66 ± 0.04% and 0.19 ± 0.02% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively, which is lower than the corresponding polarization levels obtained with MFC for 1H to 13C polarization transfer (3.95 ± 0.05% and 0.65 ± 0.05% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively). Nevertheless, a significant 13C NMR signal enhancement with respect to thermal polarization allowed us to perform 13C MR imaging of both biologically relevant hyperpolarized molecules which can be used to produce useful contrast agents for the in vivo imaging applications.

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