An approach to fast 2D nuclear magnetic resonance at low concentration based on p‐H₂‐induced polarization and nonuniform sampling

Abstract

Recent developments in para-hydrogen-induced polarization (PHIP) methods allow the nuclear magnetic resonance (NMR) detection of specific classes of compounds, down to sub-micromolar concentration in solution. However, when dealing with complex mixtures, signal resolution requires the acquisition of 2D PHIP-NMR spectra, which often results in long experimental times.This strongly limits the applicability of these 2D PHIP-NMR techniques in areas in which high-throughput analysis is required. Here, we present a combination of fast acquisition and nonuniform sampling that can afford a 10-fold reduction in measuring time without compromising the spectral quality. This approach was tested on a mixture of substrates at micromolar concentration, for which a resolved 2D PHIP spectrum was acquired in less than 3 min.

Understanding Parahydrogen Hyperpolarized Urine Spectra: The Case of Adenosine Derivatives

“…Since hydride signals do not carry as much structural information as traditional NMR, the only reliable way of assigning signals has proven to be internal standard addition [4,7,9]. The most practical pulse sequence for hyperpolarized chemosensing [6], which can also be carried out as very fast experiments [20], resolves hydride signals (red in Figure 1) according to their mutual zero quantum (ZQ) frequency in the indirect dimension of 2D spectra. Signals of structurally similar analytes have been found to form linear patterns in the 2D ZQ plots ([6] and Figure 2).…”