Ultrafast Maximum‐Quantum NMR Spectroscopy for the Analysis of Aromatic Mixtures

Abstract

Maximum-quantum (MaxQ) NMR experiments have been introduced to overcome issues related to peak overlap and high spectral density in the NMR spectra of aromatic mixtures. In MaxQ NMR, spin systems are separated on the basis of the highest-quantum coherence that they can form. MaxQ experiments are however time consuming and methods have been introduced to accelerate them. In this article, we demonstrate the ultrafast, single-scan acquisition of MaxQ NMR spectra using spatial encoding of the multiple-quantum dimension. So far, the spatial encoding methodology has been applied only for the encoding of up to double-quantum coherences, and here we show that it can be extended to higher coherence orders, to yield a massive reduction of the acquisition time of multiquantum spectra of aromatic mixtures, and also to monitor chemical reactions.

Gradient-based pulse sequences for benchtop NMR spectroscopy

“…Methodological advances at medium magnetic fields are essential to improve performances of benchtop NMR. In this context, the with overlapped peaks [74,75].…”

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil

“…Advanced NMR methods, often based on sophisticated multidimensional ( N D) schemes, have been developed to overcome the issues of signal overlap and high spectral density, which limit the applicability of 1D NMR for mixture analysis. A particularly useful method in the case of aromatic compounds is MaxQ NMR, based on multiple‐quantum (MQ) NMR . MaxQ NMR relies on the encoding of multiple‐quantum coherences.…”

“…A particularly useful method in the case of aromatic compounds is MaxQ NMR, based on multiple-quantum (MQ) NMR. 50,51 MaxQ NMR relies on the encoding of multiple-quantum coherences. Specifically, when the highest-quantum coherence (the MaxQ) present in a given spin (2010)).…”

Quantum mechanical MRI simulations: Solving the matrix dimension problem

“…Because we focus here specifically on spatially distributed multispin processes, it is useful to find a spatially encoded magnetic resonance experiment that uses the relevant properties to the maximum possible extent. Such an experiment appeared very recently—the ultrafast “maximum-quantum” sequence ( 70 ) uses spatial encoding to create a 2D correlation spectrum between the chemical shifts of the standard transverse magnetization and the chemical shift of the highest coherence order achievable in the system. Such experiments are impossible to simulate unless detailed quantum mechanical treatment is performed in the spin subspace.…”

“…Such experiments are impossible to simulate unless detailed quantum mechanical treatment is performed in the spin subspace. The spectra themselves are nothing special—a few peaks on the 2D plane that tell something useful to chemists ( 70 )—but wall clock times and matrix dimension statistics are again pertinent (Table 4).…”