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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. new psychoactive substances and cutting agents. A tool based on the determination of intramolecular isotopic profiles has been developed to provide origin discrimination with a new way to profile seized cutting agents and heroin samples. Whereas stable isotope analyses by mass spectrometry give the bulk isotopic composition, nuclear magnetic resonance gives direct access to the position‐specific isotope content at natural abundance. This report shows how both 13C NMR spectrometry and 13C, 15N MS might provide complementary and valuable information to link seized caffeine and paracetamol to their origin. Here, isotopic ratio monitoring by 13C NMR (irm‐13C NMR) offers additional benefits over irm‐MS in its capability to determine a detailed isotopic profile, leading to a better method to distinguish different caffeine and paracetamol batches. [ABSTRACT FROM AUTHOR]

Triacylglycerols, which are quasi-universal components of food matrices, consist of complex mixtures of molecules. Their site-specific C content, their fatty acid profile, and their position on the glycerol moiety may significantly vary with the geographical, botanical, or animal origin of the sample. Such variables are valuable tracers for food authentication issues. The main objective of this work was to develop a new method based on a rapid and precise C-NMR spectroscopy (using a polarization transfer technique) coupled with multivariate linear regression analyses in order to quantify the whole set of individual fatty acids within triacylglycerols. In this respect, olive oil samples were analyzed by means of both adiabatic C-INEPT sequence and gas chromatography (GC). For each fatty acid within the studied matrix and for squalene as well, a multivariate prediction model was constructed using the deconvoluted peak areas of C-INEPT spectra as predictors, and the data obtained by GC as response variables. This C-NMR-based strategy, tested on olive oil, could serve as an alternative to the gas chromatographic quantification of individual fatty acids in other matrices, while providing additional compositional and isotopic information. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to conceive a reactive transport model capable of providing quantitative site-specific enrichment factors for fractionation in 13C isotopic content during sorption. As test compound the model treats vanillin, for which the 13C isotopic content at natural abundance at each of the 8 carbon positions can be measured by quantitative 13C nuclear magnetic resonance spectrometry. This technique determines the isotope ratios with a resolution better than ±1‰ (0.1%) at each carbon position. Site-specific isotope fractionations were recorded in chromatography column experiments with silica RP-18 as stationary phase. The one dimensional reactive transport model accounted for the sorption/desorption behavior of 8 individual 13C-isotopomers and one 12C-isotopomer of vanillin and reproduced satisfactorily the bulk (average over the whole compound) fractionation observed during elution. After model calibration, the enrichment factors were fitted for each carbon site where a significant fractionation was recorded. To show the interest of such a transport model for environmental studies, the model, extended to three dimensions, was exploited to simulate reactive transport in an aquifer. These results show that significant 13C isotope fractionation is expected for 4 out of 8 13C-isotopomers in vanillin, and illustrate that bulk isotope ratios measured by conventional compound specific isotope analysis and mass spectrometry would hardly document significant isotope fractionations in vanillin. It is concluded that modeling of site-specific isotope ratios in molecules is a priori feasible and may help to quantify unknown processes in the environment. [Copyright &y& Elsevier]

For the last ten years, quantitative isotope ratio monitoring 13 C NMR (irm- 13 C NMR) has been successfully tested and proven as an efficient tool for the determination of position-specific 13 C/ 12 C ratios. Several applications in different domains have shown the interest in this technique. In the context of origin assignment, the possibility to track the distribution network of illicit drugs or cutting agents is of prime importance. However irm- 13 C NMR still suffers from a relative lack of sensitivity limiting its dissemination among control laboratories. Improvements were proposed to reduce experiment time by using the INEPT sequence ("Insensitive Nuclei Enhanced by Polarization Transfer") based on polarization transfer from highly sensitive 1 H to less sensitive 13 C. Several applications based on the use of the one bond scalar coupling between 1 H and 13 C ( 1 J CH ) have shown the potential of this methodology in terms of short experimental duration. However, the isotopic information given by quaternary carbons was lost. The aim of this study is to extend this approach by using short- and long-range coupling ( 1 J CH , 2 J CH , and 3 J CH ) in order to have access to all 13 C/ 12 C position-specific ratios, i.e., acquisition of the full spectrum (FS-INEPT). It is shown that this innovative tool provides both sensitivity gain-thanks to the long-range polarization transfer-and appropriate repeatability. The relative isotopic profiles allowed the classification of two cutting agents, caffeine and paracetamol (acetaminophen), according to their origin, as it was previously observed with "classical" irm- 13 C NMR but consuming much less sample and/or reducing the experimental time.

This present study identifies a number of azolyl-substituted indoles as potent inhibitors of aromatase. In the sub-series of 3-(azolylmethyl)-1H-indoles, four imidazole derivatives and their triazole analogues were tested. Imidazole derivatives 11 and 14 in which the benzyl moiety was substituted by 2-chloro and 4-cyano groups, respectively, were the most active, with IC50 values ranging between 0.054 and 0.050 microM. In the other sub-series, eight 3-(alpha-azolylbenzyl)-1H-indoles were prepared and tested. Compound 30, the N-ethyl imidazole derivative, proved to be an aromatase inhibitor, showing an IC50 value of 0.052 microM. All target compounds were further evaluated against 17alpha-hydroxylase/C17,20-lyase to determine their selectivity profile.