Profiling Volatile Constituents of Homemade Preserved Foods Prepared in Early 1950s South Dakota (USA) Using Solid-Phase Microextraction (SPME) with Gas Chromatography⁻Mass Spectrometry (GC-MS) Determination.

An essential dimension of food tasting (i.e., flavor) is olfactory stimulation by volatile organic compounds (VOCs) emitted therefrom. Here, we developed a novel analytical method based on solid-phase microextraction (SPME) sampling in argon-filled gas sampling bags with direct gas chromatography⁻mass spectrometry (GC-MS) determination to profile the volatile constituents of 31 homemade preserves prepared in South Dakota (USA) during the period 1950⁻1953. Volatile profiles varied considerably, but generally decreased in detected compounds, complexity, and intensity over three successive 2-h SPME sampling periods. Volatile profiles were generally predominated by aldehydes, alcohols, esters, ketones, and organic acids, with terpenoids constituting much of the pickled cucumber volatiles. Bisphenol-A (BPA) was also serendipitously detected and then quantified in 29 samples, at levels ranging from 3.4 to 19.2 µg/kg, within the range of levels known to induce endocrine disruption effects. Absence of BPA in two samples was attributed to their lids lacking plastic liners. As the timing of their preparation coincides with the beginning of BPA incorporation into consumer products, these jars may be some of the first BPA-containing products in the USA. To the best of our knowledge, this is the first effort to characterize BPA in and volatile profiles of rare historical foods with SPME.

A computational study of sulfur bridged cyclooctatetraenophanes.

Calculations of several thiacyclooctatetraenophanes predicted, as part of their overall geometry, substantial flattening of the cyclooctatetraene (COT) structures relative to the tub conformation generally associated with the COT molecule. The COT structures were approximately parallel to each other and the interplanar distances were predicted to be within 2.787-2.803 angstrom at the DFT/UB3YLP level of calculation. DFT/UB3LYP optimized geometries afforded significant delocalization of the COT structures in each of the thiacyclooctatetraenophanes. Hartree-Fock (HF) methods and the semi-empirical Austin Model 1 (AM1) method deviated significantly from the DFT/UB3LYP optimized geometries. Cyclooctatetraenes can undergo reversible sizing by oxidation and reduction reactions to form the aromatic dication and aromatic dianion, respectively, which could then be used to prepare molecular backbones for polymeric organometallic molecular wires. The number of bridges and the introduction of the sulfur atom have been investigated to provide disparate synthetic routes.