Enhancing 19F benchtop NMR spectroscopy by combining parahydrogen hyperpolarisation and multiplet refocusing

TY - JOUR

T1 - Enhancing 19F benchtop NMR spectroscopy by combining parahydrogen hyperpolarisation and multiplet refocusing

AU - Silva Terra, Ana

AU - Rossetto, Matheus

AU - Dickson, Claire

AU - Peat, George

AU - Uhrin, Dusan

AU - Halse, Meghan Eileen

PY - 2023/2/15

Y1 - 2023/2/15

N2 - Benchtop NMR spectrometers provide a promising alternative to high-field NMR for applications that are limited by instrument size and/or cost. 19F benchtop NMR is attractive due to the larger chemical shift range of 19F relative to 1H and the lack of background signal in most applications. However, practical applications of benchtop 19F NMR are limited by its low sensitivity due to the relatively weak field strengths of benchtop NMR spectrometers. Here we present a sensitivity-enhancement strategy that combines SABRE (Signal Amplification By Reversible Exchange) hyperpolarisation with the multiplet refocusing method SHARPER (Sensitive, Homogeneous, And Resolved PEaks in Real time). When applied to a range of fluoropyridines, SABRE-SHARPER achieves overall signal enhancements of up to 5700-fold through the combined effects of hyperpolarisation and line-narrowing. This approach can be generalised to the analysis of mixtures through the use of a selective variant of the SHARPER sequence, selSHARPER. The ability of SABRE-selSHARPER to simultaneously boost sensitivity and discriminate between two components of a mixture is demonstrated, where selectivity is achieved through a combination of selective excitation and the choice of polarisation transfer field during the SABRE step.

AB - Benchtop NMR spectrometers provide a promising alternative to high-field NMR for applications that are limited by instrument size and/or cost. 19F benchtop NMR is attractive due to the larger chemical shift range of 19F relative to 1H and the lack of background signal in most applications. However, practical applications of benchtop 19F NMR are limited by its low sensitivity due to the relatively weak field strengths of benchtop NMR spectrometers. Here we present a sensitivity-enhancement strategy that combines SABRE (Signal Amplification By Reversible Exchange) hyperpolarisation with the multiplet refocusing method SHARPER (Sensitive, Homogeneous, And Resolved PEaks in Real time). When applied to a range of fluoropyridines, SABRE-SHARPER achieves overall signal enhancements of up to 5700-fold through the combined effects of hyperpolarisation and line-narrowing. This approach can be generalised to the analysis of mixtures through the use of a selective variant of the SHARPER sequence, selSHARPER. The ability of SABRE-selSHARPER to simultaneously boost sensitivity and discriminate between two components of a mixture is demonstrated, where selectivity is achieved through a combination of selective excitation and the choice of polarisation transfer field during the SABRE step.

U2 - 10.1021/acsmeasuresciau.2c00055

DO - 10.1021/acsmeasuresciau.2c00055

M3 - Article

SN - 2694-250X

VL - 3

SP - 73

EP - 81

JO - ACS Measurement Science Au

JF - ACS Measurement Science Au

IS - 1

ER -