Generalised magnetisation-to-singlet-order transfer in nuclear magnetic resonance

Abstract

A variety of pulse sequences have been described for converting nuclear spin magnetisation into long-lived singlet order for nuclear spin-1/2 pairs.

Single-scan measurements of nuclear spin singlet order decay rates

“…The gradient G 3 makes the 180 degrees pulses also space selective; the intensity g 3 is set equal to g 1 while the duration d 3 is adjusted to match the length of the 180 degrees shaped pulse, sp 180 . A shaped pulse played on resonance (pulse offset o off = 0) alongside to the gradient G 1 and with bandwidth BW addresses a slice at the centre of the coil with thickness TH given in eqn (2). To target a different position along the z-axis it is sufficient to change o off (in both positive and negative direction) and the slice position with respect to the coil center is given by…”

“…NMR methodologies that exploit various aspects of long-lived nuclear spin singlet order -all groupable under the name singlet NMR -are under constant development. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The three main properties of this form of spin order -NMR silent, accessible on demand and long-lived -have found a variety of applications including: quantification, with enhanced sensitivity, of ligand binding; 18,19 measurements of very slow translational dynamics; [20][21][22][23][24][25] and their exploitation as molecular tags that can preserve information over a long time. [26][27][28][29][30][31][32][33][34][35][36] Long-lived spin order is exploited as a vehicle to preserve spin hyperpolarization gained through techniques such as PHIP, 37 SABRE 38 and dissolution-DNP.…”

In vitro singlet state and zero-quantum encoded magnetic resonance spectroscopy: Illustration with N-acetyl-aspartate

“…Nowadays, numerous pulse sequences exist, including recently proposed broad-band generalized magnetization-to-singlet-order transfer [65]. The optimum performance of such sequences covers a significant range of coupled spin systems.…”

Nuclear Spin Relaxation of Longitudinal and Singlet Order in Liquid-CO2 Solutions

“…All longitudinal decay constants (T 1 ) reported in this paper have been measured with a standard inversion recovery experiment. To measure singlet order decay constants (T S ) we have used a sequence (Figure 4) where firstly any singlet order possibly present in the sample from the previous scan is destroyed (Rodin et al, 2019), singlet order is subsequently produced with either a M2S (Pileio et al, 2010) or gM2S (Bengs et al, 2020) pulse sequence, depending on the actual spin system features. The singlet order is then allowed to relax in a specific magnetic field for some variable delay time before being reconverted back into transverse magnetization by a S2M or gS2M and acquired.…”