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HPLC-MS Detection of Nonylphenol Ethoxylates and Lauryl Ethoxylates in Foodstuffs and the Inner Coatings of High-Barrier Pouches
The widespread use of non-ionic surfactants, e.g., nonylphenol ethoxylates or dodecyl ethoxylates, may result in their occurrence in foodstuffs. In this paper, extracts from the coatings and from the contents of high-barrier food pouches were analyzed by high-pressure liquid chromatography–mass spectrometry. These flexible pouches are an alternative package format of growing interest which can replace traditional cans. In almost all samples, nonylphenol ethoxylates and dodecyl ethoxylates were detected. The identified nonylphenol ethoxylates usually contained 4–10 oxyethylene units, while the identified dodecyl ethoxylates contained 3–13 oxyethylene units. However, in a few samples, longer fractions of dodecyl ethoxylates were detected, namely those containing >15 oxyethylene units. A comparison of the non-ionic surfactant concentrations in the coating extracts with their concentrations in the content extracts indicated that the coating materials were not the main sources of the contents’ contamination. Other contaminants, namely BADGE conjugates and cyclic cooligoesters, which are common contaminants of canned foodstuffs, were found to rarely occur in high-barrier food pouches. Unexpectedly, in one sample polypropylene glycol was detected at a low concentration; this compound has not been previously identified as a potential food contaminant.
Structure elucidation of quercetin- and myricetin-O‐glycosides from the seeds of Trifolium repens
HPLC-MS Identification of the Most Abundant Flavonoid Glycosides in the Pods of Abelmoschus esculentus – Comments on the Published Data
Post-Column Guanosine Addition as a Screening Tool in the Search for Effective G-Quadruplex Binders - A Case Study of Achyrocline satureioides Phenolic Compounds
Polyphenols make a numerous and diverse group of plant secondary metabolites exhibiting remarkable anticancer activities, often attributed to their G-quadruplex binding properties. Therefore, there is a need to develop a high–throughput screening assay which would permit the evaluation of polyphenols’ binding properties toward G-quadruplex. As deoxyguanosine and guanosine are essential and key building blocks of G-quadruplexes, the stabilities of their adducts with polyphenols may reflect the stabilities of polyphenols–G-quadruplex adducts. In this study, deoxyguanosine/guanosine post-column addition experiments have been performed during HPLC-MS analysis of Achyrocline satureioides extract. The stabilities of the deoxyguanosine/guanosine adducts with 3-O-methylquercetin-7-O-glucoside, 4′-hydroxydehydrokawain-4′-O-glucoside, and 3,5-di-O-caffeoylquinic acid—compounds identified in the Achyrocline satureioides extract—have been tested by using collision-induced dissociation ‘in-source’. The obtained results show that the identified compounds form more stable adducts with deoxyguanosine and guanosine than the standards used for comparison, namely isoquercitrin and rutin. The performed molecular docking provided some insight into the structure of the adducts and revealed that multiple interactions are of key importance for their stabilities.