spectroscopy

Radiocarbon measurements with mid-infrared SCAR spectroscopy

Since its first invention and demonstration [1], saturated-absorption cavity ring-down spectroscopy (SCAR) of CO2 gas samples at 4.5 µm wavelength has been approaching accelerator mass spectrometry (AMS) precision in radiocarbon measurements. The first intercomparison between SCAR and AMS measurements was performed with modern (fermentation of brown cane sugar) and fossil (high-purity industrial gas cylinder) carbon dioxide samples [2].

Lab-on-chip for integrated cell culture monitoring

Conductance spectroscopy, performed by measuring the electrical complex conductivity of the sample, can be a valid analytical method for cell cultures monitoring. The electromagnetic properties of inhomogeneous materials, and in particular of biological materials, are expressed in terms of complex conductivity, or permittivity, and are strictly related to shape, dimensions, volume fraction occupied by the particulate (cells) [1].

Reactivity of contact ion pairs in a charged monotopic receptor

An integrated FT-ICR and computational approach has been employed to investigate the gas phase structure and reactivity of ESI-formed complexes between organic and inorganic acids (HX) and a K+-containing hexaazamacrocycle (M). Two limiting structures are available to those complexes, either the classical [MK+·XH] or the zwitterionic [MH+·K+·X?] one, with the latter prevailing over the first by increasing the gas-phase acidity of the HX ligand.

Structural and energetic properties of La3+ in water/DMSO mixtures

By using molecular dynamics based on a custom polarizable force field, we have studied the solvation of La3+ in an equimolar mixture of dimethylsulfoxide (DMSO) with water. An extended structural analysis has been performed to provide a complete picture of the physical properties at the basis of the interaction of La3+ with both solvents. Through our simulations we found that, very likely, the first solvation shell in the mixture is not unlike the one found in pure water or pure DMSO and contains 9 solvent molecules.

Multi-technique characterisation of commercial alizarin-based lakes

The characterization of ancient and modern alizarin-based lakes is a largely studied topic in the literature. Analytical data on contemporary alizarin-based lakes, however, are still poor, though of primary importance, since these lakes might be indeed present in contemporary and fake paintings as well as in retouchings. In this work we systematically investigate the chemical composition and the optical features of fifteen alizarin-based lakes, by a multi-analytical technique approach combining spectroscopic methods (i.e.

The use of micro-energy dispersive X-ray fluorescence spectrometry (μ-XRF) combined with a multivariate approach to determine element variation and distribution in tobacco seedlings exposed to arsenate

Here, we present a new scheme of analysis combining micro-energy dispersive X-ray fluorescence spectrometry (μ-XRF) with a multivariate approach that allows to establish the inter-correlation of multiple elements and their elemental map in plants. The main advantage of this procedure is that XRF spectral profiles can be analysed directly, by means of principal component analysis (PCA), allowing a quick interpretation of the results.

Dried red chili peppers pungency assessment by visible and near infrared spectroscopy

Chili peppers are widely used in many cuisines all around the world for enhancing dishes hotness. For this reason, a fast, reliable, non-destructive and not-invasive method is needed to measure and control the content of hotness in red chili peppers could be quite useful in respect of their use. Visible - Near InfraRed Spectroscopy (Vis-NIRS) fits well this purpose. The work explores the possible utilization of a portable spectroradiometer, to evaluate the spiciness of dried red chili peppers, along others important properties such as moisture content and ash content.

Aqueous polythiophene electrosynthesis. A new route to an efficient electrode coupling of PQQ-dependent glucose dehydrogenase for sensing and bioenergetic applications

In this study, polythiophene copolymers have been used as modifier for electrode surfaces in order to allow the immobilization of active pyrroloquinoline quinone dependent glucose dehydrogenase (PQQ-GDH) and to simultaneously improve the direct electrical connection of the enzyme with the electrode. Polymer films are electrosynthesized in aqueous solution without the need of surfactants onto carbon nanotubes modified gold electrodes from mixtures of 3-thiopheneacetic acid (ThCH2CO2H) and 3-methoxythiophene (ThOCH3) using a potentiostatic pulse method.

The market of chiral drugs: chiral switches versus de novo enantiomerically pure compounds

This review article is aimed at providing an overview of the current market of chiral drugs by exploring which is the nowadays tendency, for the pharmaceutical industry, either to exploit the chiral switching practice from already marketed racemates or to develop de novo enantiomerically pure compounds. A concise illustration of the main techniques developed to assess the absolute configuration (AC) and enantiomeric purity of chiral drugs has been given, where greater emphasis was placed on the contribution of enantioselective chromatography (HPLC, SFC and UHPC).

Recognition mechanism of aromatic derivatives resolved by argentation chromatography: The driving role played by substituent groups

Argentation chromatography is widely used nowadays as a powerful tool to separate complex mixtures of analytes containing unsaturated and/or aromatic fragments. Here we present the results of chromatographic and computational studies on a silver-thiolate stationary phase, in which the silver metal is covalently bonded to mercaptopropyl silica particles. The exceptionally high selectivity displayed by this organometallic moiety prompted us to deeply investigate its molecular recognition properties.

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