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Cobas C.,Mestrelab Research S.L. | Seoane F.,Mestrelab Research S.L. | Vaz E.,Mestrelab Research S.L. | Bernstein M.A.,Mestrelab Research S.L. | And 3 more authors.
Magnetic Resonance in Chemistry | Year: 2013

A novel data-evaluation procedure for the automatic atom to peak or multiplet assignment of 1H-NMR spectra of small molecules has been developed using a fast and robust expert system. The applicability and reliability of the method are demonstrated by comparison of a manually assigned database of 1H-NMR spectra with the assignments produced by the automatic procedure. The results of this analysis show an excellent success ratio, indicating that this new algorithm can have a major impact as a time saving tool for the organic chemist. A new graphical feature used to illustrate both the stability and quality of the elementary assignments is also introduced. Copyright © 2013 John Wiley & Sons, Ltd. Source


Bortolotti V.,University of Bologna | Fantazzini P.,University of Bologna | Gombia M.,University of Bologna | Rinaldin G.,University of Bologna | Sykora S.,Extra Byte
Journal of Magnetic Resonance | Year: 2010

Parametrically Enabled Relaxation FIlters with Double and multiple Inversion (PERFIDI) is an experimental NMR/MRI technique devised to analyze samples/voxels characterized by multi-exponential longitudinal relaxation. It is based on a linear combination of NMR sequences with suitable preambles composed of inversion pulses. Given any standard NMR/MRI sequence, it permits one to modify it in a way which will attenuate, in a predictable manner and before data acquisition, signals arising from components with different r rates (r = 1/T1). Consequently, it is possible to define relatively simple protocols to suppress and/or to quantify signals of different components. This article describes a simple way to construct low-pass, high-pass and band-pass PERFIDI filters. Experimental data are presented in which the method has been used to separate fat and water proton signals. We also present a novel protocol for very fast determination of the ratio between the fat signal and the total signal which avoids any time-consuming magnetization recovery multi-array data acquisition. The method has been validated also for MRI, producing well T 1-contrasted images. © 2010 Elsevier Inc. All rights reserved. Source


Bernstein M.A.,S.L. Feliciano Barrera | Sykora S.,Extra Byte | Peng C.,S.L. Feliciano Barrera | Barba A.,S.L. Feliciano Barrera | Cobas C.,S.L. Feliciano Barrera
Analytical Chemistry | Year: 2013

NMR is routinely used to quantitate chemical species. The necessary experimental procedures to acquire quantitative data are well-known, but relatively little attention has been applied to data processing and analysis. We describe here a robust expert system that can be used to automatically choose the best signals in a sample for overall concentration determination and determine analyte concentration using all accepted methods. The algorithm is based on the complete deconvolution of the spectrum which makes it tolerant of cases where signals are very close to one another and includes robust methods for the automatic classification of NMR resonances and molecule-to-spectrum multiplets assignments. With the functionality in place and optimized, it is then a relatively simple matter to apply the same workflow to data in a fully automatic way. The procedure is desirable for both its inherent performance and applicability to NMR data acquired for very large sample sets. © 2013 American Chemical Society. Source


Fratila R.M.,University of Twente | Gomez M.V.,University of Castilla - La Mancha | Sykora S.,Extra Byte | Velders A.H.,University of Twente | And 2 more authors.
Nature Communications | Year: 2014

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique, but its low sensitivity and highly sophisticated, costly, equipment severely constrain more widespread applications. Here we show that a non-resonant planar transceiver microcoil integrated in a microfluidic chip (detection volume 25 nl) can detect different nuclides in the full broad-band range of Larmor frequencies (at 9.4 T from 61 to 400 MHz). Routine one-dimensional (1D) and two-dimensional (2D), homo- and heteronuclear experiments can be carried out using the broad-band coil set-up. Noteworthy, heteronuclear 2D experiments can be performed in a straightforward manner on virtually any combination of nuclides (from classical 1 H- 13 C to more exotic combinations like 19 F- 31 P) both in coupled and decoupled mode. Importantly, the concept of a non-resonant system provides magnetic field-independent NMR probes; moreover, the small-volume alleviates problems related to field inhomogeneity, making the broad-band coil an attractive option for, for example, portable and table-top NMR systems.© 2014 Macmillan Publishers Limited. All rights reserved. Source


Schoenberger T.,Bundeskriminalamt KT12 | Menges S.,Bundeskriminalamt KT12 | Bernstein M.A.,S.L. Feliciano Barrera | Perez M.,S.L. Feliciano Barrera | And 3 more authors.
Analytical Chemistry | Year: 2016

Quantitative 1H NMR (qNMR) is a widely applied technique for compound concentration and purity determinations. The NMR spectrum will display signals from all species in the sample, and this is generally a strength of the method. The key spectral determination is the full and accurate determination of one or more signal areas. Accurate peak integration can be an issue when unrelated peaks resonate in an important integral region. We describe a "hybrid" approach to signal integration that provides an accurate estimation of signal area, removing the component(s) that may arise from unrelated peaks. This is achieved by using the most accurate integration method for the region and removing unwanted contributions. The key to this performing well, and in almost all cases, is the use of areas from deconvolved peaks. We describe this process and show that it can be very successfully applied to cases where the highest precision is required and for more common cases of NMR-based quantitation. (Chemical Equation Presented). © 2016 American Chemical Society. Source

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