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Gold nanoparticles (AuNPs) are functionalized with a thermoresponsive polymer shell of a cross-linked poly(2-(2-methoxyethoxy)ethyl methacrylate) (P(MEO 2 MA)). To provide a covalent attachment of the polymer to the NP surface, AuNPs are fi rst modifi ed using butanoic acid to develop the encapsulation with the biocompatible thermoresponsive polymer formed by free-radical precipitation polymerization. Both the MEO 2 MA concentration and the shell cross-linking density can be varied and, in turn, the thickness and the shells' free volume can be fi ne-tuned. By downscaling the size of the polymeric shell, the lower critical solution temperature (LCST) is decreased. The LCST in the nanohybrids changes from 19.1 to 25.6 °C when increasing the MEO 2 MA content; it reaches almost 26 °C for P(MEO 2 MA) (bulk). The maximum decrease in the volume of the nanohybrids is around 40%, resulting in a modifi cation of the light scattering properties of the system and causing a change in the turbidity of the gel network. The sizes of the nanohybrids are characterized using both transmission electron microscopy and dynamic light scattering measurements. Optical properties of the colloidal systems are determined using the derived count rate measurements as an alternative to absorbance or transmittance measurements, confi rming the colloidal stability of the nanohybrid systems.

This work explores the application of chemometric techniques to Raman spectra to study aged lipidic paint binders. These binders, commonly known as drying oils, were widely used by artists throughout history both individually and in mixtures. We prepared various model samples of the pure binders (linseed, poppy-seed and walnut oils and egg yolk) and of binary mixtures thereof. These model samples were left to age naturally for six years and further characterized by Raman spectroscopy. A comparative study of the Raman spectral features before and after ageing process was carried out. This showed changes mainly in the bands located at 1267, 1655 and 3011 cm–1, which correspond to vibrations in cis double bonds. Multivariate analysis was performed by applying principal component analysis and partial least-squares discriminant analysis on the corresponding Raman spectra to test whether spectral differences allowed samples to be distinguished on the basis of their composition. The CH stretching region was found to be especially useful for discrimination between the different binders. Furthermore, good sensitivity and specificity were found in the discriminant analysis particularly for the identification of binders containing egg yolk. The results of these multivariate analyses demonstrated the potential use of both chemometric approaches in the field of Cultural Heritage for drying oil characterization and identification, and also for gaining a deeper insight into the ageing process. Copyright © 2011 John Wiley & Sons, Ltd.

This paper presents a new application for monolithic columns with low-pressure chromatographic separation using an flow injection analysis configuration with chemiluminescent detection for the determination of a mixture of phenolic compounds: phloroglucinol, 2,4-dihydroxybenzoic acid, salicylic acid, methyl paraben and n-propyl gallate. The procedure consists of the separation of these compounds on a reverse-phase ultra-short monolithic column with pH 3.0 acetate buffer and 5% acetonitrile as carrier phase. The detection is based on a chemiluminescence measurement coming from Ce(IV)–Rhodamine 6G chemistry with the incorporation of two different chemiluminescent chemical conditions in the chromatographic setup in order to enhance the sensitivity for the different phenolic compounds. All separation and detection variables were optimized to propose a determination method. The analysis is performed in 280?s, with the sampling frequency being some 13 h−1. The calibration function is a double reciprocal function obtaining good results within two orders of magnitude. The limits of detection were 8.8 × 10 −8 m (phloroglucinol), 2.7 × 10 −8 m (2,4-dihydroxybenzoic acid); 2.3 × 10 −8 m (salicylic acid); 5.2 × 10 −8 m (methyl paraben) and 4.1 × 10 −6 m (n-propyl gallate), and the relative standard deviations at a medium level of the linear range were 4.4% (phloroglucinol), 2.8% (2,4-dihydroxybenzoic acid), 5.2% (salicylic acid), 3.6% (methyl paraben) and 6.8% (n-propyl gallate). The method was applied and validated satisfactorily for the determination of these compounds in healthcare products, comparing the results against an HPLC reference method. Copyright © 2009 John Wiley & Sons, Ltd.

Polarographic behaviour of Schiff bases derived from 2-pyrrolecarboxaldehyde and 2-thiophenecarboxaldehyde has been investigated in 50%, dioxane-water medium in pH range 4 to 10. The experimental conditions for the study were so chosen that no appreciable hydrolysis of the Schiff bases occurred during the recording of polarograms. Schiff bases gave two well separated monoelectronic waves in the pH range studied, which shifted to more negative potentials as the pH was increased. Dependence of diffusion current on concentration of depolarizer and height of mercury reservoir suggest that both the waves are diffusion controlled. On the basis of the polarographic and cyclic voltammetry data an overall electrode reaction is given.

We report two methods that have allowed the attachment of glu- cose, mannose and lactose to one or both of the cyclopentadienyl rings of ferrocene. The resulting ferrocene-car- bohydrate conjugates were synthesised by the reaction of thioglycosides with ferrocenemethanol and 1,1'-ferrocene- dimethanol in acidic media. A second method based on the regiospecific cop- per(I)-catalysed cycloaddition of prop- argyl glycoside, azidomethyl and bis- Arocene as well as azi- doethyl glycoside and ethynylferrocene was also used and led to the synthesis of 1,2,3-triazole-containing glycoconju- gates. The electrochemical behaviour of the synthesised glycoconjugates was investigated. In addition, their binding interactions with b-cyclodextrin were studied by means of NMR spectrosco- py, isothermal titration calorimetry, and cyclic and differential pulse vol- tammetric experiments. These tech- niques allowed the determination of the thermodynamic parameters of the complexes, the stability constants for the complexes formed with both the neutral and the oxidised states of the ferrocenyl glycoconjugates, the mode of inclusion and the diffusion coeffi- cients for both the glycoconjugates and the complexes.