Free sugars quantification in intact plant tissue by HR-MAS NMR.

2013-07-24Methods & Applications, Our Publicationsfood-science, HRMAS, method-comparison, quantitative nmr, sugar-contentMiquel

“Assessment of a 1H high-resolution magic angle spinning NMR spectroscopy procedure for free sugars quantification in intact plant tissue” Teresa Delgado-Goñi, Sonia Campo, Juana Martín-Sitjar, Miquel E. Cabañas, Blanca San Segundo, Carles Arús; Planta, 238:397-413, 2013 (PDF file). DOI: 10.1007/s00425-013-1924-y

In most plants, sucrose is the primary product of photosynthesis, the transport form of assimilated carbon, and also one of the main factors determining sweetness in fresh fruits. Traditional methods for sugar quantification (mainly sucrose, glucose and fructose) require obtaining crude plant extracts, which sometimes involve substantial sample manipulation, making the process time-consuming and increasing the risk of sample degradation. Here, we describe and validate a fast method to determine sugar content in intact plant tissue by using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR). Continue reading Free sugars quantification in intact plant tissue by HR-MAS NMR. →

On the interference of J_HH modulation in HSQMBC-IPAP and HMBC-IPAP experiments

2013-07-15Methods & Applications, Our Publications, Our ResearchHMBC, HSQMBC, IPAP, proton-carbon coupling constantsJosep

“On the interference of J(HH) modulation in HSQMBC-IPAP and HMBC-IPAP experiments”, by Josep Saurí and Teodor Parella; Magn. Reson. Chem. 2013. DOI: 10.1002/mrc.3977

The effects of phase signal modulation due to homonuclear proton–proton coupling constants in HSQMBC-IPAP and HMBC-IPAP experiments are experimentally evaluated. An assessment of the reliability ofⁿJ_CH measurement from distorted cross-peaks obtained in IPAP versions of HMBC and HSQMBC experiments is presented. Continue reading On the interference of J_HH modulation in HSQMBC-IPAP and HMBC-IPAP experiments →

NaAlH₄ confined in Ordered Mesoporous Carbon

2013-07-13Our Publications23Na-NMR, 27Al-NMR, hydrides, ordered_mesoporous_carbon, solid-state nmrPau

NaAlH4 confined in Ordered Mesoporous Carbon

Bonatto, C.; Lindemann, I.; Nolis, P.; KieBling, A.; Baró, M. D.; Klose, M.; Giebler, L.; Rellinghaus, B.; Eckert, J.; Schultz, L.; Gutfleisch, O.

In this paper we performed a comprehensive investigation of the structural and sorption properties of a 40 wt. % NaAlH₄ confined in a ordered mesoporous carbon (OMC, i.e. CMK-3) by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), ²³Na{¹H} and ²⁷Al{¹H} solid-state magic angle spinning-nuclear magnetic resonance (MAS-NMR).

This study evidences a remarkable improvement of the sorption kinetics of NaAlH₄ due to its existence in nanometer size within the OMC. The pressure composition isotherm (PCI) analysis (for the re-absorption step) of the nanoconfined NaAlH₄ would suggest an alteration of its equilibrium thermodynamic properties.

Enantiodiscrimination Studies by ¹³C DNP-NMR Spectroscopy

2013-06-27Seminars13C-NMR, chirality, hyperpolarizationEva

SeRMN Seminar

Date: Thursday 27th June, 2013
Hour: 3 pm
Location: SeRMN, Facultats de Ciències i Biociències, C2/-135
Speaker: Eva Monteagudo, technician at SeRMN, UAB

Continue reading Enantiodiscrimination Studies by ¹³C DNP-NMR Spectroscopy →

Presentations to the EUROMAR 2013 Conference

2013-06-20News from the SeRMN, NMR Events & Courses, Our ResearchLaura

In a few days several SeRMN members will present our research work at the annual meeting of the European magnetic resonance community EUROMAR 2013 Conference that will take place in Hersonissos, Crete (Greece) from 30^th June to 5^th July. Find below a summary of our contributions. Continue reading Presentations to the EUROMAR 2013 Conference →

Gelation process followed by NMR

2013-06-11Our Publicationschirality, foldamers, gelation, hydrogen-bonds, organogels, peptides, secondary structures, self-assemblyPau

Low-molecular-weight gelators consisting of hybrid cyclobutane-based peptides, by Sergi Celis, Pau Nolis, Ona Illa, Vicenç Branchadell, Rosa M. Ortuño, Organic & Biomolecular Chemistry 2013, 11, 2839 DOI: 10.1039/c3ob27347d

Some hybrid tetrapeptides consisting of (1R,2S)-2-aminocyclobutane-1-carboxylic acid and glycine, β-alanine, or γ-aminobutyric acid (GABA) joined in alternation, compounds 1–3, respectively, have been investigated to gain information on the non-covalent interactions responsible for their self-assembly to form ordered aggregates, as well as on parameters such as their morphology and size. All three peptides formed nice gels in many organic solvents and significant difference in their behaviour was not observed. Continue reading Gelation process followed by NMR →

CLIP-HSQMBC: Very easy, direct and accurate measurement of ⁿJ_CH in organic molecules and natural products

2013-05-29Methods & Applications, Our Publications, Our ResearchHSQMBC, proton-carbon coupling constantsJosep

CLIP-HSQMBC: Easy measurement of small proton-carbon coupling constants in organic molecules, by Josep Saurí, Teodor Parella and Juan F. Espinosa; Org. Biomol. Chem., 2013, 11, 4473-4478. DOI:10.1039/C3OB40675J

A user-friendly 2D NMR approach denoted as CLIP-HSQMBC is proposed for the very easy, direct and accurate measurement of long-range proton-carbon coupling constants in organic molecules and natural products. The J value can be extracted directly from the analysis of resolved in-phase 1H multiplets that show an additional splitting arising from the proton-carbon coupling. Continue reading CLIP-HSQMBC: Very easy, direct and accurate measurement of ⁿJ_CH in organic molecules and natural products →

NMR confirms cysteine labelling with SFB in peptides

2013-05-14Our Publicationspeptides, PET, strucutural characterizationPau

“Efficient cysteine labelling of peptides with N-succinimidyl 4-[18F]fluorobenzoate: stability study and in vivo biodistribution in rats by positron emission tomography ( PET)” by Santiago Rojas, Pau Nolis, Juan D. Gispert, Jan Spengler, Fernando Albericio, José R. Herance, Sergio Abad. RSC Advances. 2013. DOI: 10.1039/C3RA40754C

A rapid and high-yielding cysteine labelling of peptides has been observed with the specific labelling agent for amines, N-succinimidyl 4-[¹⁸F]fluorobenzoate ([¹⁸F]SFB). Interestingly, NMR demonstrates that conjugation of the 4-fluorobenzoyl (FB) moiety is selectively achieved through a cysteine (Cys) thiol of the peptides with high yield (>80%) in short time (<5 min), while for a Cys amino acid derivative, a slow process has been observed. Continue reading NMR confirms cysteine labelling with SFB in peptides →

J-selHSQMBC: Simultaneous measurement of J_HH and two different ⁿJ_CH using IPAP, J-resolved and E.COSY principles

2013-05-10Methods & Applications, Our Publications, Our ResearchE.COSY, HSQMBC, IPAP, J-resolved, proton-carbon coupling constants, proton-proton coupling constantsJosep

cover_MRC “Simultaneous measurement of J(HH) and two different ⁿJ(CH) coupling constants from a single multiply-edited 2D cross-peak”, by Josep Saurí and Teodor Parella; Magn. Reson. Chem. 2013, 51, 397-402. DOI: 10.1002/mrc.3960

Three different J-editing methods (IPAP, E.COSY and J-resolved) are implemented in a single NMR experiment to provide spin-state-edited 2D cross-peaks from which simultaneous measurement of different homonuclear and heteronuclear coupling constants can be performed. Continue reading J-selHSQMBC: Simultaneous measurement of J_HH and two different ⁿJ_CH using IPAP, J-resolved and E.COSY principles →

Measurement of the sign and the magnitude of small heteronuclear coupling constants

2013-05-06Seminarsproton-carbon coupling constantsJosep

SeRMN seminar

Date: Friday 10th May, 2013
Hour: 10 am
Location: SeRMN, Facultats de Ciències i Biociències, C2/-135
Speaker: Josep Saurí, SeRMN PhD Student

Continue reading Measurement of the sign and the magnitude of small heteronuclear coupling constants →

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