Hyperpolarised 1H-13C benchtop NMR spectroscopy

TY - JOUR

T1 - Hyperpolarised 1H-13C benchtop NMR spectroscopy

AU - Robinson, Alastair David

AU - Richardson, Peter Michael

AU - Halse, Meghan Eileen

N1 - © 2019 by the authors

PY - 2019/3/20

Y1 - 2019/3/20

N2 - Benchtop NMR spectrometers with sub-ppm spectral resolution have opened up new opportunities for performing NMR outside of the standard laboratory environment. However, the relatively weak magnetic fields of these devices (1 - 2 T) results in low sensitivity and significant peak overlap in 1H NMR spectra. Here we use hyperpolarised 13C{1H} NMR to overcome these challenges. Specifically, we demonstrate the use of the signal amplification by reversible exchange (SABRE) parahydrogen-based hyperpolarisation technique to enhance the sensitivity of natural abundance 1D and 2D 13C{1H} benchtop NMR spectra. We compare two detection methods for SABRE-enhanced 13C NMR and observe an optimal 13C{1H} signal-to-noise ratio (SNR) for a refocused INEPT approach, where hyperpolarisation is transferred from 1H to 13C. In addition, we exemplify SABRE-enhanced 2D 13C benchtop NMR through the acquisition of a 2D HETCOR spectrum of 260 mM of 4-methylpyridine at natural isotopic abundance in a total experiment time of 69 mins. In theory, signal averaging for over 300 days would be required to achieve a comparable SNR for a thermally polarised benchtop NMR spectrum acquired of a sample of the same concentration at natural abundance

AB - Benchtop NMR spectrometers with sub-ppm spectral resolution have opened up new opportunities for performing NMR outside of the standard laboratory environment. However, the relatively weak magnetic fields of these devices (1 - 2 T) results in low sensitivity and significant peak overlap in 1H NMR spectra. Here we use hyperpolarised 13C{1H} NMR to overcome these challenges. Specifically, we demonstrate the use of the signal amplification by reversible exchange (SABRE) parahydrogen-based hyperpolarisation technique to enhance the sensitivity of natural abundance 1D and 2D 13C{1H} benchtop NMR spectra. We compare two detection methods for SABRE-enhanced 13C NMR and observe an optimal 13C{1H} signal-to-noise ratio (SNR) for a refocused INEPT approach, where hyperpolarisation is transferred from 1H to 13C. In addition, we exemplify SABRE-enhanced 2D 13C benchtop NMR through the acquisition of a 2D HETCOR spectrum of 260 mM of 4-methylpyridine at natural isotopic abundance in a total experiment time of 69 mins. In theory, signal averaging for over 300 days would be required to achieve a comparable SNR for a thermally polarised benchtop NMR spectrum acquired of a sample of the same concentration at natural abundance

U2 - 10.3390/app9061173

DO - 10.3390/app9061173

M3 - Article

SN - 2076-3417

VL - 9

JO - Applied Sciences

JF - Applied Sciences

IS - 6

M1 - 1173

ER -