Study of β-cyclodextrin inclusion complexes with volatile molecules geraniol and α-terpineol enantiomers in solid state and in solution

© 2015 Elsevier B.V. All rights reserved. Geraniol and α-terpineol are insoluble in water volatile compounds. α-Terpineol is a potentially important agent for medical applications. Formation of molecular complexes with β-cyclodextrin would lead to the increase of water solubility and bioavailability. β-Cyclodextrin forms 2:2 inclusion complexes with both enantiomers of α-terpineol and their precursor geraniol. Solid state complexes are thoroughly characterized by single X-ray crystallography and their stability over vast range of temperatures is proven by TG analysis. Intermolecular host-guest, host-host and guest-guest interactions give good insight into the nature of formed inclusion complexes. Stability constants of the complexes in solution are determined by HPLC

Separation of Enantiomers by Inclusion Gas Chromatography: On the Influence of Water in the Molecular Complexation of Methyl 2-Chloropropanoate Enantiomers and the Modified γ-Cyclodextrin Lipodex-E

A profound influence of water has previously been detected in the complexation of the enantiomers of methyl 2-chloropropanoate (MCP) and the chiral selector octakis(3-O-butanoyl-2,6-di-O-pentyl)-γ-cyclodextrin (Lipodex-E) in NMR and sensor experiments. We therefore investigated the retention behavior of MCP enantiomers on Lipodex-E by gas chromatography (GC) under hydrous conditions. Addition of water to the N2 carrier gas modestly reduced the retention factors k of the enantiomers, notably for the second eluted enantiomer (S)-MCP. This resulted in an overall decrease of enantioselectivity -ΔS,R(ΔG) in the presence of water. The effect was fully reversible. Consequently, for a conditioned column in the absence of residual water, the determined thermodynamic data, i.e. ΔS,R(ΔH) = -12.64 ± 0.08 kJ mol-1 and ΔS,R(ΔS) = -28.18 ± 0.23 J K-1 mol-1, refer to a true 1:1 complexation process devoid of hydrophobic hydration. Chirality 28:124-131, 2015

Aquatic Ecotoxicity Testing of Nanoparticles—The Quest To Disclose Nanoparticle Effects

The number of products on the market containing engineered nanoparticles (ENPs) has increased significantly, and concerns have been raised regarding their ecotoxicological effects. Environmental safety assessments as well as relevant and reliable ecotoxicological data are required for the safe and sustainable use of ENPs. Although the number of publications on the ecotoxicological effects and uptake of ENPs is rapidly expanding, the applicability of the reported data for hazard assessment is questionable. A major knowledge gap is whether nanoparticle effects occur when test organisms are exposed to ENPs in aquatic test systems. Filling this gap is not straightforward, because of the broad range of ENPs and the different behavior of ENPs compared to “ordinary” (dissolved) chemicals in the ecotoxicity test systems. The risk of generating false negatives, and false positives, in the currently used tests is high, and in most cases difficult to assess. This Review outlines some of the pitfalls in the aquatic toxicity testing of ENPs which may lead to misinterpretation of test results. Response types are also proposed to reveal potential nanoparticle effects in the aquatic test organisms

Micellar electrokinetic chromatography with bile salts for separation of flavanone diastereomers

Sodium cholate and sodium deoxycholate were applied in the micellar electrokinetic chromatography technique as separating agents for the diastereomers of flavanone glycosides. The effects of the organic solvent buffer modifier, bile salt type and concentration were evaluated for enhancing distereomer separation. The critical micelle concentration of sodium cholate and sodium deoxycholate in the applied running buffer was determined. The bi nding constants of flavanone glycosides to bile salts micelle were estimated. The elaborated analytical method was used to analyse the flavanone fraction of bitter orange (Citrus aurantium) and grapefruit (Citrus paradisi) juice.Cholan sodu i deoksycholan sodu zostały zastosowane w technice micelarnej elektrokinetycznej chromatografii cieczowej jako czynnik rozdzielający diastereomery glikozydów flawanonów. Oceniono wpływ rozpuszczalnika organicznego jako modyfikatora buforu, typu soli żółciowej oraz jej stężenia na wzmocnienie rozdzielenia diastereomerów. Wyznaczono krytyczne stężenie micelarne cholanu sodu i deoksycholanu sodu w zastosowanym buforze rozdzielającym. Oszacowano stałe trwałości glikozydów flawanonów z micelami soli żółciowych. Opracowana metoda została wykorzystana do analizy frakcji flawanonowej w soku gorzkiej pomarańczy (Citrus aurantium) i grejfruta (Citrus paradise)