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A fully automated isotopic profile deconvoluted chromatogram (IPDC) algorithm (Fakouri Baygi et al. in Anal Chem 91:15509–15517, 2019) and user interactive HaloSeeker 1.0 (Léon et al. in Anal Chem 91:3500–3507, 2019) were compared to test the efficacy of these two computationally enhanced non-targeted screening (CENTS) tools in isolating unknown Br/Cl compounds using high-resolution mass spectrometry (HRMS) data. HaloSeeker depends on a user to monitor the performance of the peak picking algorithm and assign molecular formulas for each isotopic signature in an ergonomic interface. Alternatively, the IPDC algorithm automatically assigns and ranks candidate molecular formulas within a set of search criteria. Both CENTS tools were evaluated using fish and sediment data acquired at 22,000 (mHRMS) and > 100,000 (uHRMS) mass resolutions, respectively. The IPDC algorithm detected 85% of compounds detected by HaloSeeker as the first candidate compound in the sediment sample, with fewer false positives. In the sediment data, the IPDC algorithm detected several compounds such as clofoctol and chlorinated paraffins that were not reported using HaloSeeker 1.0. Upon further inspection, these compounds were isolated by the HaloSeeker program, but not reported by the user. HaloSeeker detected all significant and insignificant chemical ionization products (relative to IPDC), but additional false positives were isolated in the mHRMS polychlorinated biphenyl reference standard and trout sample. HaloSeeker detected 62% of the legacy contaminant features isolated by the IPDC algorithm in the fish data (mHRMS). The comparison of these two CENTS tools demonstrates that matrix complexity and mass resolution of the HRMS platform are the key factors when choosing automated and user interactive CENTS tools. [ABSTRACT FROM AUTHOR]

The article presents the isotopic profiling of natural uranium mined from northern Nigeria for nuclear forensic application.

Four mined samples of natural uranium from northern Nigeria were studied through inductively coupled plasma mass spectrometry, at the Environmental Analytical Chemistry Laboratory, University of the Witwatersrand, Johannesburg. The samples were characterised for lead, thorium and uranium isotopic concentrations, isotopic ratios and age. The objective was to obtain nuclear forensic fingerprints as baseline data to add to the Nigerian National Nuclear Forensic Library. Results showed significant variation in the isotopic concentrations of lead, thorium and uranium across the mines. Isotopic ratios of 238U/235U, 235U/238U and 234U/238U across the sample of 137.881±0.007, 7.253×10-03±2.05×10-04 and 5.540×10-05±4.08×10-07 were found to be consistent with the natural values. The age of natural uranium is comparable to the age of earth. Uranium, lead, and thorium isotopic concentrations and ratios, as well as the age of the samples characterised, provide an isotopic profile that can be used for nuclear forensic application. Significance: • Given the abundant deposits of natural uranium in Africa and the consequent potential for nuclear insecurity, determining the isotopic profiles and signatures of natural uranium is important for application in nuclear forensics. • Isotopic concentrations of 232Th, 238U, 235U and 234U from the respective sampling sites differed significantly, thereby providing characteristic isotopic profiles.

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]

In a previous work, we optimized and used a fast adiabatic 13 C-INEPT (Insensitive Nuclei Enhanced by Polarization Transfer) experiment for the isotopomic analysis of olive oil samples, which allowed us quantifying individual fatty acids within triacylglycerols through multivariate linear regression models. The goal of this study was to validate these models and to evaluate the power of 13 C-INEPT in the authentication of olive oils relative to gas chromatography (GC) and 1 H NMR. In this respect, a new set of olive oil samples was analyzed by these three techniques. The analytical variables thus obtained as well as their corresponding long-term repeatability were compared. As a result, the reliability of the fatty acid quantification models was proven and the best classification of olive oils according to the altitude of the olive grove and to the morphological aspect (color) of the olives was achieved by means of 13 C-INEPT. [ABSTRACT FROM AUTHOR]

An optimized HSQC sequence was tested and applied to triacylglycerol matrices to determine their isotopic and metabolomic profiles. Spectral aliasing and non-uniform sampling approaches were used to decrease the experimental time and to improve the resolution, respectively. An excellent long-term repeatability of signal integrals was achieved enabling to perform isotopic measurements. Thirty-two commercial vegetable oils were analyzed by this methodology. The results show that this method can be used to classify oil samples according to their geographical and botanical origins. [ABSTRACT FROM AUTHOR]

The new complete molecular confidence (CMC) concept explores the synergies of the analytical techniques LC-MS and NMR to obtain an estimation of the purity, concentration, and identity of chemical compounds. The high mass accuracy of the MS and MS/MS data provided by the new generation of ESI-TOF and ESI-Q-TOF mass spectrometers provides an accurate determination of molecular weight, which is used specifically for the structural verification and purity determination of substances. The high separation of the isotope profile for both MS and MS/MS spectra affords further dimensions of information to achieve precise molecular formula determination. By performing a complete NMR spectral analysis, the automated consistency analysis routine provides a safe assessment of the consistency between molecular structure and H NMR spectrum. The routine returns the fully assigned spectrum and the accurate NMR parameters extracted from the experimental data. Absolute quantification of a series of samples can be automatically performed including the whole workflow from sample setup, automatic NMR measurements, analysis, and spread-sheet reporting. This allows determining mass contents, relative amounts of substances, and purity. The strategy is explored on a set of 96 different pyrrole derivates. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

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 13 C NMR spectrometry and 13 C, 15 N MS might provide complementary and valuable information to link seized caffeine and paracetamol to their origin. Here, isotopic ratio monitoring by 13 C NMR (irm- 13 C 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., (© 2019 John Wiley & Sons, Ltd.)