Thermodynamic parameters and stoichiometries for the binding of anilinonaphthalenesulfonates to beta-cyclodextrin are obtained from steady-state fluorescence intensity and anisotropy measurements. Specifically, formation constant, enthalpy, and entropy values are obtained for complexes of beta-cyclodextrin with eight different substrate molecules at five different temperatures and six different pH values, and their associated errors are given. We propose an explanation of the relative magnitudes of the values obtained with regard to the geometry of the substrate and the importance of the various noncovalent interactions responsible for the complexation.

Thermodynamic study on the effects of beta-cyclodextrin inclusion with anilinonaphthalenesulfonates.

The concentrations of 11 phenols and 5 furans were measured in 12 categories of distilled spirits by HPLC methodology, together with the total antioxidant status (TAS) of the same beverages. Ellagic acid was the phenol present in highest concentration in all beverages. Moderate amounts of syringaldehyde, syringic acid, and gallic acid, as well as lesser amounts of vanillin and vanillic acid, were measurable in most samples of whiskey, brandy, and rum but were largely undetectable in gin, vodka, liqueurs, and miscellaneous spirits. 5-(Hydroxymethyl)furfural was the predominant furan in the former three beverages, notably cognac, with 2-furaldehyde the next highest, but these were undetectable in most of the latter beverages. Highest TAS values were given by armagnac, cognac, and bourbon whiskey, all three of which tended toward the highest concentrations of phenols. Negative TAS values were exhibited by rum, vodka, gin, and miscellaneous spirits in line with the low or undetectable phenol concentrations in these beverages. Wood aging is the most likely source of phenols and furans in distilled spirits. Those beverages exposed to this treatment contain significant antioxidant activity, which is between the ranges for white and red wines, with the potential to augment the antiatherosclerotic functions attributable to the ethanol that they contain.

Phenolic constituents, furans, and total antioxidant status of distilled spirits.

Introduction "Vaping" electronic cigarettes (e-cigarettes) is increasingly popular with youth, driven by the wide range of available flavors, often created using flavor aldehydes. The objective of this study was to examine whether flavor aldehydes remain stable in e-cigarette liquids or whether they undergo chemical reactions, forming novel chemical species that may cause harm to the user. Methods Gas chromatography was used to determine concentrations of flavor aldehydes and reaction products in e-liquids and vapor generated from a commercial e-cigarette. Stability of the detected reaction products in aqueous media was monitored by ultraviolet spectroscopy and nuclear magnetic resonance spectroscopy, and their effects on irritant receptors determined by fluorescent calcium imaging in HEK-293T cells. Results Flavor aldehydes including benzaldehyde, cinnamaldehyde, citral, ethylvanillin, and vanillin rapidly reacted with the e-liquid solvent propylene glycol (PG) after mixing, and upward of 40% of flavor aldehyde content was converted to flavor aldehyde PG acetals, which were also detected in commercial e-liquids. Vaping experiments showed carryover rates of 50%-80% of acetals to e-cigarette vapor. Acetals remained stable in physiological aqueous solution, with half-lives above 36 hours, suggesting they persist when inhaled by the user. Acetals activated aldehyde-sensitive TRPA1 irritant receptors and aldehyde-insensitive TRPV1 irritant receptors. Conclusions E-liquids are potentially reactive chemical systems in which new compounds can form after mixing of constituents and during storage, as demonstrated here for flavor aldehyde PG acetals, with unexpected toxicological effects. For regulatory purposes, a rigorous process is advised to monitor the potentially changing composition of e-liquids and e-vapors over time, to identify possible health hazards. Implications This study demonstrates that e-cigarette liquids can be chemically unstable, with reactions occurring between flavorant and solvent components immediately after mixing at room temperature. The resulting compounds have toxicological properties that differ from either the flavorants or solvent components. These findings suggest that the reporting of manufacturing ingredients of e-liquids is insufficient for a safety assessment. The establishment of an analytical workflow to detect newly formed compounds in e-liquids and their potential toxicological effects is imperative for regulatory risk analysis.

Formation of flavorant–propylene Glycol Adducts With Novel Toxicological Properties in Chemically Unstable E-Cigarette Liquids

Study on the interaction of methylene blue with cyclodextrin derivatives by absorption and fluorescence spectroscopy

Evaluation of the relative effectiveness of different water-soluble .beta.-cyclodextrin media to function as fluorescence enhancement agents

Quinizarin (1,4-dihydroxyanthraquinone) and β-cyclodextrin (β-CD) form a 1 : 1 inclusion complex with an estimated association constant of 200 l mol–1 at pH 7.1. The hydrophobic nature of β-CD helps to dissolve and stabilise the dye and hence permits its use as a ligand in coordination reactions with metal ions. This inclusion compound has been used for the fluorimetric determination of trace amounts of scandium. A limit of detection of < 1 ng ml–1 of scandium was obtained with a relative standard deviation of 5%. The method was free from interferences from 40 species tested at concentration ratios below 1 : 1 m/m.

Fluorimetric determination of scandium using the cyclodextrin-1,4-dihydroxyanthraquinone inclusion complex

http://www.biblioteca.uma.es/bbldoc/articulos/16742606.pdf

Enhanced fluorimetric determination of procaine in pharmaceutical preparations by aqueous β- cyclodextrin inclusion and non-aqueous competitive action

A graphical derivative approach to the photometric determination of lutetium and praseodymium in mixtures

Spectrofluorimetric determination of beryllium based on the inclusion complex of 1-amino-4-hydroxyanthraquinone with β-cyclodextrin as ligand

A derivative spectrophotometric procedure for the simultaneous determination of vanillin (4-hydroxy-3-methoxybenzaldehyde) and syringaldehyde (4-hydroxy-3,5-dimethoxybenzaldehyde) in rum is described. The method minimises the mutual interference between vanillin and syringaldehyde and allows the determination of these compounds without a previous extraction step. The precision of the method, expressed as the relative standard deviation, is better than 4%.

http://atarazanas.sci.uma.es/docs/articulos/16759229.pdf

M. Hernandez Lopez

Papers

Fluorimetric determination of scandium using the cyclodextrin-1,4-dihydroxyanthraquinone inclusion complex

Enhanced fluorimetric determination of procaine in pharmaceutical preparations by aqueous β- cyclodextrin inclusion and non-aqueous competitive action

A graphical derivative approach to the photometric determination of lutetium and praseodymium in mixtures

Spectrofluorimetric determination of beryllium based on the inclusion complex of 1-amino-4-hydroxyanthraquinone with β-cyclodextrin as ligand

Simultaneous determination of vanillin and syringaldehyde in rum by derivative spectrophotometry