Differentiation of bisphenol F diglycidyl ether isomers and their derivatives by HPLC-MS and GC-MS-comment on the published data

Gas Phase Reactivity of Isomeric Hydroxylated Polychlorinated Biphenyls

Identification of stereo- and positional isomers detected with high-resolution mass spectrometry (HRMS) is often challenging due to near-identical fragmentation spectra (MS2), similar retention times, and collision cross-section values (CCS). Here we address this challenge on the example of hydroxylated polychlorinated biphenyls (OH-PCBs) with the aim to (1) distinguish between isomers of OH-PCBs using two-dimensional ion mobility spectrometry (2D-IMS) and (2) investigate the structure of the fragments of OH-PCBs and their fragmentation mechanisms by ion mobility spectrometry coupled to high-resolution mass spectrometry (IMS-HRMS). The MS2 spectra as well as CCS values of the deprotonated molecule and fragment ions were measured for 18 OH-PCBs using flow injections coupled to a cyclic IMS-HRMS. The MS2 spectra as well as the CCS values of the parent and fragment ions were similar between parent compound isomers; however, ion mobility separation of the fragment ions is hinting at the formation of isomeric fragments. Different parent compound isomers also yielded different numbers of isomeric fragment mobilogram peaks giving new insights into the fragmentation of these compounds and indicating new possibilities for identification. For spectral interpretation, Gibbs free energies and CCS values for the fragment ions of 4'-OH-CB35, 4'-OH-CB79, 2-OH-CB77 and 4-OH-CB107 were calculated and enabled assignment of structures to the isomeric mobilogram peaks of [M-H-HCl]- fragments. Finally, further fragmentation of the isomeric fragments revealed different fragmentation pathways depending on the isomeric fragment ions.

Comment on Hu et al. Determination of 2-Pentanol Enantiomers via Chiral GC-MS and Its Sensory Evaluation in Baijiu. Foods 2022, 11, 2584

Recently, Hu et al. have published a very interesting paper concerning the GC-MS analysis of 2-pentanol enantiomers in four types of Baijiu, a strong alcoholic beverage, which is of importance to Chinese social culture [...]

Terahertz spectral identification and low-frequency vibrational analysis of dinitrotoluene isomers

Identifying dinitrotoluene (DNT) isomers has always been a challenging problem. In this study, five DNT isomers were investigated using terahertz time-domain spectroscopy (THz-TDS), which demonstrated significant spectral differences including variations in absorption positions and intensities. This suggests that THz-TDS is ideal for rapid identification of DNT isomers. We also employed density functional theory to further discuss the origin of these spectral differences. The results indicate that steric effects between substitute groups, rather than inter-molecular hydrogen bonding, lead to differences in low-frequency vibrations.

Ethoxylated Butoxyethanol-BADGE Adducts-New Potential Migrants from Epoxy Resin Can Coating Material

The acetonitrile extracts of can-coating materials have been analyzed by using high-pressure liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS). On the basis of detected ions [M + H]⁺, [M + NH₄]⁺, [M + Na]⁺ and product ions, the ethoxylated butoxyethanol-bisphenol A diglycidyl ether adducts were identified in two of the analyzed extracts. Although the oxyethylene unit-containing compounds are widely used for the production of different kinds of materials, the ethoxylated species have not been earlier detected in epoxy resin can-coatings.

A guide towards safe, functional and renewable BPA alternatives by rational molecular design: structure–property and structure–toxicity relationships

Putting the pieces together: a guide for rational molecular design of safe, functional and renewable BPA alternatives.