Hadamard NMR spectroscopy

Fast targeted multidimensional NMR metabolomics of colorectal cancer

“…As in conventional Fourier transform 2D spectroscopy, single scans add up constructively. [19] The number of one-dimensional (1D) spectra to be recorded is determined by the number of selected resonance frequencies or frequency regions and not by the dwell time which determines the sweep width and therewith the resolution of conventional spectra. The Hadamard-encoding procedure yields pseudo-2D spectra that can be recorded in a time frame similar to that of 1D spectra.…”

“…There are several review articles which describe and compare the different options of recording Hadamard-encoded spectra. [19] Other authors have previously used selective TOCSYs for metabolomics although not in conjunction with Hadamard encoding. [20,21] Here, we apply Hadamard-encoded TOCSYs to analyze samples from colorectal cancer patients compared with normal controls and samples from adenoma patients.…”

“…Some authors have employed two-dimensional (2D) HSQC spectroscopy in connection with nonlinear sampling for faster acquisition and maximum entropy reconstruction [18] but such spectra still require hours of acquisition time and are not suitable for high throughput applications. Here, we show how Hadamard-encoded NMR spectroscopy [19] can be used to deconvolute NMR spectra of blood serum from colorectal cancer patients. This approach enables samples to be analyzed almost as rapidly as by one-dimensional NMR spectroscopy, typically requiring just 10-20 min of acquisition time.…”

Improving resolution in single-scan 2D spectroscopy

“…An advantage of this method is that it does not lead to a loss in signal-to-noise, apart from minor losses induced by relaxation during the bandselective pulse. If two separate experiments are carried out with a phase shift, the signal-to-noise increases with each scan, like in Hadamard spectroscopy [28]. This method is particularly advantageous when there are empty regions in the spectrum and could be generalized to shift more than one region by applying multiple BPP-BSRP elements.…”

Time‐shared NMR experiments

“…Some examples should be the rapid pulsing combined with Ernst angle excitation (4), simultaneous acquisition of related experiments using Hadamard encoding (5), fast acquisition of multidimensional experiments using the reduced dimensionality (RD) approach combined with GFT (6), spectral reconstruction methods using projection-reconstruction (7) or nonlinear data sampling (8) techniques or collection of different experiments in different parts of the same sample using spatial encoding (known as single-scan NMR) (9), among others. In addition, it has also been demonstrated that the combination of some of these techniques can afford accumulative advantages (10,11).…”