A combination of molecular modeling, DFT calculations, and advanced solid-state NMR experiments is used to elucidate the supramolecular structure of a series of benzoxazine oligomers. Intramolecular hydrogen bonds are characterized and identified as the driving forces for ring-shape and helical conformations of trimeric and tetrameric units. In fast MAS (1)H NMR spectra, the resonances of the p...

molecular modeling analysis of charge density and heat of fornation by pm3 method as well as c, h nmr and 2d-nmr measurements of histidine (substrate) and some of its derivatives as histidine decarboxylase inhibitors were performed. it was established that the atom, usually nitrogen, which forms internal aldimine with pyridoxal5 -phosphate (plp), (coenzyme), has negative and almost equal charge...

A simple approach is reported that yields high resolution, high sensitivity H NMR spectra of intact biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle and at a spinning rate of about 80Hz. A 2D pulse sequence called H PASS is used to produce a high-resolution H NMR spectrum that is free from magnetic susceptibility i...

NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (¹H, (13)C, and (31)P) and two-dimensional (¹H-(13)C and ¹H-(31)P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. ¹H, (13)C, and (31)P NMR signal...

Dissolution dynamic nuclear polarization (DNP) enables high-sensitivity solution-phase NMR experiments on long-lived nuclear spin species such as (15)N and (13)C. This report explores certain features arising in solution-state (1)H NMR upon polarizing low-γ nuclear species. Following solid-state hyperpolarization of both (13)C and (1)H, solution-phase (1)H NMR experiments on dissolved samples r...

PURPOSE The aim of the study was to find an appropriate method for determination of the attachment degree of polyethylene glycol (PEG) to poly(anhydride) nanoparticles. METHODS The nanoparticles were modified with hydroxy-functionalized or with amino-functionalized PEGs. Three methods for their determination were applied and examined: in particular colorimetry, nuclear magnetic resonance ( (1...

Analytical methods based on spectroscopic techniques were developed and validated for the determination of diethyl phthalate (DEP) and polyhexamethylene guanidine (PHMG), which may occur in unrecorded alcohol. Analysis for PHMG was based on UV-VIS spectrophotometry after derivatization with Eosin Y and (1)H NMR spectroscopy of the DMSO extract. Analysis of DEP was performed with direct UV-VIS a...

A simple modification of the WATERGATE solvent suppression method greatly improves the quality of (1)H NMR spectra obtainable from samples in H(2)O. The new method allows (1)H signals to be measured even when close in chemical shift to the signal of water, as for example in the NMR spectra of carbohydrates.

A system that provides a sustained hyperpolarized (1)H NMR signal in an aqueous medium is reported. The enhanced signal lasts much longer than typical (1)H T(1) values, uncovering new possibilities for implementing hyperpolarized (1)H NMR/MRI experiments or performing kinetics studies that would not otherwise be detectable.

BACKGROUND There is no comprehensive analytical technique to analyze N-acetylated metabolites in urine. Many of these compounds are involved in inborn errors of metabolism. In the present study, we examined the potential of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy as a tool to identify and quantify N-acetylated metabolites in urine of patients with various inborn errors of meta...