Characterization of chemicals in household products is important for understanding this potential source of chemical exposure. Increasingly, suspect screening and nontargeted analysis techniques are used to characterize as many chemical signatures as possible. Solids such as household products are most conveniently prepared using solvent extraction, revealing what chemicals are contained within the product matrix but providing no information about the potential of those chemicals to leave the matrix and cause actual exposure. In this work, the profile and relative abundances of “extractable” chemical signatures found after solvent extraction are compared to those “emittable” to the headspace for 81 household products analyzed by two-dimensional gas chromatography time-of-flight mass spectrometry. This study retrospectively fuses data collected in separate efforts over 3.8 years and 13 analytical batches. Management of the data is made possible by recent developments in processing systems for complex data such as Highlight. Compounds were generically classified as aromatic heteroatom, aromatic hydrocarbon, glycol, hydrocarbon, long chain heteroatom, nonaromatic heteroatom, and unknown/unclassified. Class-based retention time and abundance trends were observed. Liquid extraction resulted in the greatest number of features and the highest relative abundances, while low temperature emission conditions produced the smallest number of features and lowest relative abundances.

Introduction Melanoma is an aggressive form of cancer characterised by its high metabolic adaptability that contributes to drug resistance. To this end, ruthenium complexes have emerged as a promising...

This study employs a combination of orthogonal chromatographic and detection techniques to screen and characterise hydrogenated vegetable oils (HVOs), addressing the question of whether HVOs share the...

Using GC×GC-TOFMS, TMIC and Natural Resources Canada identify wood species to fight illegal logging and support sustainable forestry.

Growing evidence suggests that alkylated derivatives of polycyclic aromatic hydrocarbons (PAHs) should be considered in toxicity assessment, necessita…

AbstractA quantitation method for n-alkanes, branched alkanes, cycloalkanes, and alkenes in mixtures has been developed based on two-dimensional gas chromatography (GCxGC)/positive ion-mode 70 eV electron ionization time-of-flight mass spectrometry ((+)EI TOF MS). Chromatographic peak areas for 50 standard model compounds in a concentration range from 0.5 up to 10 mM were obtained using GC×GC coupled with flame ionization detection (FID) and directly compared with the peak area response of the same standards obtained by using GC×GC/(+)EI TOF MS. Empirical normalized correction factors for each standard were calculated as the relationship between the peak area response for the FID and the (+)EI TOF MS at each concentration with respect to an internal standard of a fixed concentration, i.e., 1-methylnaphthalene at a concentration of 2 mM. Linear empirical correction factors to adjust the raw peak areas measured using (+)EI TOF MS with respect to the number of carbon atoms were found for n-alkanes, polysubstituted alkanes, and polysubstituted alkenes, while a quadratic relationship was found for n-alkylcyclohexanes. No linear or polynomial relationships were found between the normalized correction factors and the number of carbon atoms for disubstituted alkanes, disubstituted alkenes, and polycycloalkanes. However, specific normalized correction factors and weighing factors are proposed for their quantitation by using (+)EI TOF MS. The influence of the degree of branching of the analytes on their ionization efficiency upon EI and their response in FID and, therefore, on their empirical correction factors, is discussed.

The objective of this study was to characterize the metabolic profile of tuberculous meningitis (TBM) in the cerebrospinal fluid (CSF) of a South African pediatric cohort using two-dimensional gas chromatography linked to time-of-flight mass spectrometry (GCxGC-TOFMS). A metabolite extraction and derivatization protocol was performed using CSF samples from 21 cases of bacteriologically confirmed TBM and 24 controls without meningitis, and analyzed by GCxGC-TOFMS, followed by univariate and multivariate statistical comparisons to identify differentiating compounds. A total of 48 metabolites (involved in glycolysis and amino acid and fatty acid metabolism) were identified that differentiated the two groups (effect size d-value > 0.5 and partial least squares discriminant analysis VIP value > 1.0, with 16 metabolites highlighted as significant (p-value < 0.05). Eight novel metabolites (linked to imines, alkenes, and volatile organic compounds), never before identified in a TBM study, characterize TBM in this cohort. This study confirms existing metabolomics research aimed at characterizing the metabolic profile of TBM. Some affected metabolic pathways include glycolysis, pentose phosphate pathway, amino acids, and fatty acid metabolism. New information is provided on the effect TBM has on neurometabolism, how TBM can reduce the neuroprotective function of some metabolites in the brain, resulting in the neurological symptoms typically associated with this disease, and contribute to our understanding of the pathogenesis of TBM; ultimately, contributing to the development of a metabolic model of TBM.

Consumer products are a major source of chemicals that may pose a health risk. It is important to understand what chemicals are in these products to evaluate risk and assess new products for uncommon ingredients. Suspect screening analysis (SSA) using two-dimensional gas chromatography-high-resolution-time-of-flight/mass spectrometry (GCxGC-HR-TOF/MS) was applied to 92 consumer products from 5 categories. 485 probable chemical structures were tentatively identified using the NIST 2017 spectral library across all products (109 confirmed). Chemicals were characterized by functional use and structural class. Fabric upholsteries contained the most chemicals (239) identifiable by GCxGC-HR-TOF/MS and silicone kitchen tools the least (64). Use of duplicate samples and repeat purchases of products allowed for a within-product category similarity assessment, which showed highest variability in baby soap and lowest in cotton clothing. Chemical ingredient signatures (including reported sample abundance ranges) for each product type were obtained by identifying chemicals occurring in ≥80% of product samples. These signatures provide a baseline set of chemical ingredients (that is, representative mixtures) across common consumer product types. The chemical signatures will help in evaluating new and existing products. Separating constituent chemicals into typical and atypical might inform exposure assessment, in vitro bioactivity screening, and ultimately the risk related to using such products.

## Riepilogo OggettoItalia – Gascromatografi – GCXGC ToFMS - PROCEDURA APERTA Stazione appaltanteFondazione Edmund Mach StatoGara aggiudicata TED IDeb617667-2ba5-41cf-aeba-60d5c6494d13 ### This post is for subscribers only Become a member to get access to all content Subscribe now

## Riepilogo OggettoItalia – Gascromatografi – GCXGC ToFMS - PROCEDURA APERTA Stazione appaltanteFondazione Edmund Mach StatoGara aggiudicata TED IDeb617667-2ba5-41cf-aeba-60d5c6494d13 ### This post is for subscribers only Become a member to get access to all content Subscribe now

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Científicas y científicos de la Universidad Nacional Autónoma de México (UNAM) investigarán compuestos químicos presentes en mezclas complejas de la atmósfera mediante el sistema PEGASUS BTX, un equipo especializado en Cromatografía de Gases Bidimensional (GCxGC).