Reversible Light-Triggered Stretching of Small-Molecule Photochromic Organic Nanoparticles.

Functional organic nanomaterials are nowadays largely spread in the field of nanomedicine. In situ modulation of their morphology is thus expected to considerably impact their interactions with the surroundings. In this context, photoswitchable nanoparticles that are manufactured, amenable to extensive disassembling upon illumination in the visible, and reversible reshaping under UV exposure.

NMR metabolite quantification of a synthetic urine sample: an inter-laboratory comparison of processing workflows.

Introduction: Absolute quantification of individual metabolites in complex biological samples is crucial in targeted metabolomic profiling.

Objectives: An inter-laboratory test was performed to evaluate the impact of the NMR software, peak-area determination method (integration vs. deconvolution) and operator on quantification trueness and precision.

Exploring the enantiomeric C position-specific isotope fractionation: challenges and anisotropic NMR-based analytical strategy.

Trying to answer the intriguing and fundamental question related to chiral induction/amplification at the origin of homochirality in Nature: "Is there a relationship between enantiomeric and isotopic fractionation of carbon 13 in chiral molecules?" is a difficult but stimulating challenge. Although isotropic C-PSIA NMR is a promising tool for the determination of (C/C) ratios capable of providing key C isotopic data for understanding the reaction mechanisms of biological processes or artificial transformations, this method does not provide access to any enantiomeric C isotopic data unless mirror-image isomers are first physically separated. Interestingly, C spectral enantiodiscriminations can be potentially performed in situ in the presence of enantiopure entities as chiral-europium complexes or chiral liquid crystals (CLCs).

Forensic application of position-specific isotopic analysis of trinitrotoluene (TNT) by NMR to determine C and N intramolecular isotopic profiles.

2,4,6-trinitrotoluene (TNT) is a molecule which is easily identified with current instrumental techniques but it is generally impossible to distinguish between sources of the same substance (TNT). To overcome this difficulty, we present a multi stable isotope approach using isotope ratio monitoring by mass spectrometry (irm-MS) and Nuclear Magnetic Resonance spectrometry (irm-NMR). In the one hand, irm-MS provides bulk isotopic composition at natural abundance in C and N.

Isotopomics by isotope ratio monitoring by C nuclear magnetic resonance spectrometry on cutting agents in heroin: A new approach for illicit drugs trafficking route elucidation.

In the battle against the illicit drugs market, methodologies have been developed by forensic laboratories to address the determination of the origin and dismantlement of the trafficking route for various target molecules such as heroin and cocaine. These drug profiling methods are not straightforward, especially when the target molecules are synthetic and very pure, resulting in poorly informative impurity profiles, e.g.