In Situ SABRE Hyperpolarization with Earth’s Field NMR Detection

Abstract

Hyperpolarization methods, which increase the sensitivity of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI), have the potential to expand the range of applications of these powerful analytical techniques and to enable the use of smaller and cheaper devices. The signal amplification by reversible exchange (SABRE) method is of particular interest because it is relatively low-cost, straight-forward to implement, produces high-levels of renewable signal enhancement, and can be interfaced with low-cost and portable NMR detectors. In this work, we demonstrate an in situ approach to SABRE hyperpolarization that can be achieved using a simple, commercially-available Earth’s field NMR detector to provide 1H polarization levels of up to 3.3%. This corresponds to a signal enhancement over the Earth’s magnetic field by a factor of ε > 2 × 108. The key benefit of our approach is that it can be used to directly probe the polarization transfer process at the heart of the SABRE technique. In particular, we demonstrate the use of in situ hyperpolarization to observe the activation of the SABRE catalyst, the build-up of signal in the polarization transfer field (PTF), the dependence of the hyperpolarization level on the strength of the PTF, and the rate of decay of the hyperpolarization in the ultra-low-field regime.

Different cellulosic polymers for synthesizing silver nanoparticles with antioxidant and antibacterial activities

“…In brief, an aqueous solution of each sample was adjusted to ≈25 °C and then exposed to a laser beam of ≈633 nm at a scattering angle of ≈90 ° . The obtained results were calculated as the average of the three measurements, whereas each measurement was run ≈20 times (with a ≈10 s duration) 64 .…”

Integrating Micro Process Chemistry into an NMR Spectrometer

“…In this work, the highly reproducible signal enhancement facilitated SABRE hyperpolarized multi-dimensional NMR benchtop spectroscopy. In addition, Hill-Casey et al [92] explored a similar automated bubbling setup for in situ SABRE experiments in the Earth magnetic field, in which the build-up process of observable SABRE hyperpolarized signal was a function of the total parahydrogen bubbling time (Fig. 4b)).…”

Nuclear hyperpolarization of (1-13C)-pyruvate in aqueous solution by proton-relayed side-arm hydrogenation

“…Spin density operators represent each point in time marked by bold numbers assuming J 13 = 0 and ignoring any relaxation or deviations from the weak-coupling condition. 2 H decoupling was used throughout the whole sequence and is not shown. The intervals τ 1 and τ 5 are given by τ 1 = 1/(2J 23 ) and τ 5 = 1/(2J 34 ).…”

“…Hyperpolarization methods are a group of techniques that address the limited sensitivity of Nuclear Magnetic Resonance (NMR). [1][2][3][4][5][6][7][8][9] These methods have led to promising progress towards highly polarized molecules for use in the chemical and biological sciences as molecular imaging agents 8,10,11 some of which are already on their way to clinical diagnostics. [12][13][14] Among the several metabolic substrates that have been hyperpolarized, (1-13 C)-pyruvate is, by far, the most widely investigated.…”

“…[12][13][14][15][16][17] One of the fastest hyperpolarization methods is parahydrogen-induced polarization (PHIP). 2,3,7,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] It has a number of advantages, such as its low-cost, compact and easy application without the need of dedicated cryo-cooled high-field magnets, and the ability to produce large quantities of polarized material on demand. The method uses spin order from the para-spin isomer of molecular hydrogen which is provided by chemical interactions between a substrate of interest, solvent and a catalyst.…”