Veronica Novelli

High-performance liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in honey

Abstract A method of determination of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in honey by high-performance liquid chromatography (HPLC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives of carbonyl compounds is thus avoided and direct injection of the sample into the PHLC system is allowed. The procedure offers a high specificity, since the derivatives of F and HMF are well separated from the other components of the mixture under examination. Recoveries of 95–99% were obtained from honey spiked at different levels with both analytes. The detection limit is of the order of 10 μg/kg of honey and reproducibility (mean of six determinations) is ±3% for F and ±2% for HMF.

Liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in beer

Abstract A method for the determination of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in beer by liquid chromatography (LC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives of carbonyl compounds is thus avoided and direct injection of the sample into the LC system is possible. The procedure offers a high specificity, since the derivatives of F and HMF are well separated from the other components of the mixture under examination. Recoveries of 91–98% were obtained from beer spiked at different levels with both analytes. The detection limit is in the order of 10 −8 mol/l and the reproducibility (mean of six determinations) is ±5% for F and ±3% for HMF.

High Performance Liquid Chromatographic Determination of 2-Furaldehyde and 5-Hydroxymethyl-2-Furaldehyde in Processed Citrus Juices

Abstract The occurrence of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in processed citrus juices is an indication of quality deterioration. A close relationship between flavor changes and F content exists, while HMF can give rise to browning reactions. Both F and HMF are formed during heat processing or storage at improper temperatures. The detection of these compounds becomes more and more important as aseptic processing and packaging of citrus juices are becoming widespread. Aseptic packaging allows higher temperatures during distribution and storage to be employed without microbial spoilage, but off-flavors develop as citrus products are exposed to these conditions. In this paper a method of determination by high performance liquid chromatography (HPLC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,...

High-performance liquid chromatographic determination of 2-furaldehyde in spirits

Official methods for the determination of 2-furaldehyde in spirits involve for a spectrophotometric evaluation, which is characterized by poor specificity. Gas chromatographic evaluations have also been proposed, which offer a much higher sensitivity, particularly when capillary columns are used. In this paper a high-performance liquid chromatographic (HPLC) method based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives is described. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives is avoided and direct injection of the sample into the HPLC system is allowed. The determination offers a high specificity and a detection limit of the order of 10(-8) mol/l. Accuracy and reproducibility data are presented.

Determination of cadmium and lead in vegetables by stripping chronopotentiometry

A method for the determination of cadmium and lead in vegetables by stripping chronopotentiometric analysis, after digestion of the sample with concentrated sulphuric acid and dry-ashing, is described. Metal ions were concentrated as their amalgams on a glassy carbon-working electrode previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally derived and E was plotted versus dt/dE−1, thus increasing both the sensitivity of the method and the resolution of the analysis. Quantitative analysis was carried out by the method of standard addition; good linearity was obtained in the range of examined concentrations, as was shown by the determination coefficients, which were 0.998 (n = 4) for cadmium and 0.993 (n = 4) for lead. Recoveries of 85–100% for cadmium and of 84–97% for lead were obtained from a sample spiked at different levels. Accuracy was demonstrated by analysis of a matching reference sample of cabbage. The detection limits were 1.8 ng g−1 of wet mass for cadmium and 5.1 ng g−1 of wet mass for lead. The relative standard deviations (mean of nine determinations), evaluated on a real sample, were 6.7 and 6.2%, respectively. Results obtained on 10 different commercial samples of pepper (Capsicum annuum), and egg plant (Solanum melongena) were not significantly different from those obtained by graphite furnace atomic absorption spectrophotometry technique. The average content was in the range 3.1–18.6 ng g−1 for cadmium and 38.2–64.3 ng g−1 for lead.

The Complexation Reactions of N-methylated Polyamines with Silver(I) in Dimethylsulfoxide

Abstract The thermodynamic parameters for the complex formation reactions in dimethylsulfoxide (dmso) between Ag(I) and the following polyamines: N,N′-dimethylethylenediamine (dmen), N,N,N′,N′-tetramethylethylenediamine (dmen), N,N″-dimethyl-diethylenetriamine (dmdien) and N,N,N′,N″, N″-pentamethyldiethylenetriamine (pmdien) have been determined by potentiometric and calorimetric techniques at 298 K and 0.1 mol dm−3 ionic strength (NEt4ClO4). Only mononuclear complexes are formed (AgLj + j = 1,2) where the ligands act prevalently as chelate agents. All the complexes are enthalpy stabilized whereas the entropy changes counteract the complex formation. The results are discussed in terms of different basicities and steric requirements of both the ligands and the complexes formed.

Environmentally Sustainable Development in the Province of Belluno (Italy)

In recent years, the municipality of Ponte nelle Alpi, in the province of Belluno, has developed an excellent environmental policy, that has allowed it to come first place in the 2010 Italian award “Comuni Ricicloni” for separate collections of household waste, to achieve the ISO 14001 certificate in 2010 and the Emas recognition in 2011. In 2010 the municipality started the joint project PubblichEnergie, together with other local authorities, to promote the use of renewable energy sources, in particular photovoltaic energy. Informative meetings with people, enterprises, associations and local authorities were convened on the opportunities of safeguarding both environment and public health. Among the innovative aspects of the project there is the possibility of supporting a Joint Purchase Group to develop the potentials of photovoltaic technology. Furthermore, the possibility of access to promotion initiatives granted by the EU, in particular the Energy Count, is provided for.

Flow Behavior of Fresh Very High Strength Portland Cement Pastes

Flow behavior of fresh very high strength portland cement pastes prepared at various water/cement ratios was studied by using a rate-controlled coaxial cylinder viscometer (Rotovisko-Haake 20, system M5-osc., measuring device MV2P with serrated surfaces). The tests were performed under continuous flow conditions. Experimental shear stress and shear rate data were fitted very satisfactorily with various models, one of which has already been proposed by the authors. Excellent results were achieved also by applying the Quemada equation. In addition, the influence of two different commercial superplasticizing agents (Concretan RX and Ergomix 1000, the former based on polycyclic copolymers with modified structures, carrying hydroxylated side chains, and the latter on a modified polyacrylic resin) was studied with the aim of determining their optimum dosage and verifying the effectiveness by comparing rheological results with those obtained in a previous work on an ordinary portland cement. The use of superplasticizers modified rheological behavior of the pastes; however, no value of optimum dosage was found for any additive, but only a superplasticizer concentration range within which pastes presented very low values of viscosity. Moreover, both superplasticizers showed a greater effectiveness when added to HSPC pastes rather then the OPC ones formulated with the same water/cement ratio.