Toward Reliable Lipoprotein Particle Predictions from NMR Spectra of Human Blood: An Interlaboratory Ring Test.

Lipoprotein profiling of human blood by H nuclear magnetic resonance (NMR) spectroscopy is a rapid and promising approach to monitor health and disease states in medicine and nutrition. However, lack of standardization of measurement protocols has prevented the use of NMR-based lipoprotein profiling in metastudies. In this study, a standardized NMR measurement protocol was applied in a ring test performed across three different laboratories in Europe on plasma and serum samples from 28 individuals.

Precision high-throughput proton NMR spectroscopy of human urine, serum, and plasma for large-scale metabolic phenotyping.

Proton nuclear magnetic resonance (NMR)-based metabolic phenotyping of urine and blood plasma/serum samples provides important prognostic and diagnostic information and permits monitoring of disease progression in an objective manner. Much effort has been made in recent years to develop NMR instrumentation and technology to allow the acquisition of data in an effective, reproducible, and high-throughput approach that allows the study of general population samples from epidemiological collections for biomarkers of disease risk. The challenge remains to develop highly reproducible methods and standardized protocols that minimize technical or experimental bias, allowing realistic interlaboratory comparisons of subtle biomarker information.

Targeted and nontargeted wine analysis by (1)h NMR spectroscopy combined with multivariate statistical analysis. Differentiation of important parameters: grape variety, geographical origin, year of vintage.

The authenticity, the grape variety, the geographical origin, and the year of vintage of wines produced in Germany were investigated by (1)H NMR spectroscopy in combination with several steps of multivariate data analysis including principal component analysis (PCA), linear discrimination analysis (LDA), and multivariate analysis of variance (MANOVA) together with cross-validation (CV) embedded in a Monte Carlo resampling approach (MC) and others. A total of about 600 wines were selected and carefully collected from five wine-growing areas in the southern and southwestern parts of Germany. Simultaneous saturation of the resonances of water and ethanol by application of a low-power eight-frequency band irradiation using shaped pulses allowed for high receiver gain settings and hence optimized signal-to-noise ratios.

Structural studies on ionic liquid/water/peptide systems by HR-MAS NMR spectroscopy.

The present work reports on an assessment of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for structural investigations of peptides dissolved in aqueous ionic liquids. Highly resolved one- and two-dimensional NMR spectra are obtained that allow for complete proton resonance assignments of both the peptides as solutes and the ionic liquids as solvents. Successful application of the HR-MAS method facilitates for the first time high-resolution NMR analysis of complex ionic liquid/peptide systems at the molecular level, mainly on the basis of chemical-shift changes.

Application of automated eightfold suppression of water and ethanol signals in 1H NMR to provide sensitivity for analyzing alcoholic beverages.

The 400 MHz (1)H NMR analysis of alcoholic beverages using standard pulse programs lacks the necessary sensitivity to detect minor constituents such as methanol, acetaldehyde or ethyl acetate. This study investigates the application of a shaped pulse sequence during the relaxation delay to suppress the eight (1)H NMR frequencies of water and ethanol (the OH singlet of both water and ethanol, as well as the CH(2) quartet and CH(3) triplet of ethanol). The sequence of reference measurement for frequency determination followed by the suppression experiment is controlled by a macro in the acquisition software so that a measurement under full automation is possible (12 min per sample total time).