Noemi Proietti

Physical-chemical characterisation of acrylic polymers grafted on cellulose

An oxidative reaction of cellulose with sodium metaperiodate was performed. The oxidised groups were decomposed by treatment with UV light into free macroradicals. In the presence of acrylic monomers, in the vapour phase, these reactive sites become the starting points for the graft copolymerisation of the cellulose substrate. n nIn this study we examined the graft yield as a function of the polymerisation time and the oxidation degree of cellulose. The grafted polymer was characterised using several analytical techniques, DSC analysis, GPC analysis, viscosity, FTIR and 13C CP-MAS. Information on the morphology of grafted chains with respect to the bulk cellulose was obtained, measuring the dynamic parameters in a careful 13C CP-MAS NMR study. All proposed chemical reactions, if properly conducted, do not affect the crystallinity of cellulose and introduce only a very modest amount of oligomers, therefore they seem suitable for the consolidation and protection of precious cellulose based materials, which are of historical interest.

Noninvasive and nondestructive NMR, Raman and XRF analysis of a Blaeu coloured map from the seventeenth century

A complete multianalytical study of a hand-coloured map from the seventeenth century is presented. The pigments atacamite, massicot, minium, gypsum, carbon black and vermilion were determined by means of XRF and Raman spectroscopy. The state of conservation of the cellulosic support was monitored by means of unilateral NMR. The analysis was nondestructive and noninvasive, and thus several spectra were collected from the same areas, yielding more reliable results without damaging the artwork. The role of copper pigments in the oxidation processes observed in the cellulosic support is discussed, as well as the possible provenance of atacamite as a raw material instead of as a degradation product of malachite.

Analysis of a coloured Dutch map from the eighteenth century: the need for a multi-analytical spectroscopic approach using portable instrumentation.

A Dutch map from the eighteenth century was multi-analytically analysed making use of energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Raman and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The cellulosic support was characterised and its state of conservation was evaluated. Besides, paramagnetic impurities were detected together with copper metallic chips. The colours present in some areas of the map were also analysed. Vermilion, carbon black and organic pigments were found. Surprisingly, in the green areas, the rare presence of the mineral moolooite (copper oxalate) was detected. A possible biological attack is discussed in order to explain the presence of such compound. Almost all of the techniques used in the analysis were portable, non-destructive and non-invasive, which is very desirable when analysing objects belonging to Cultural Heritage. The need for a multi-analytical approach using portable instrumentation is also discussed.

Monitoring of metabolic profiling and water status of Hayward kiwifruits by nuclear magnetic resonance

The metabolic profiling of kiwifruit (Actinidia deliciosa, Hayward cultivar) aqueous extracts and the water status of entire kiwifruits were monitored over the season (June-December) using nuclear magnetic resonance (NMR) methodologies. The metabolic profiling of aqueous kiwifruit extracts was investigated by means of high field NMR spectroscopy. A large number of water-soluble metabolites were assigned by means of 1D and 2D NMR experiments. The change in the metabolic profiles monitored over the season allowed the kiwifruit development to be investigated. Specific temporal trends of aminoacids, sugars, organic acids and other metabolites were observed. The water status of kiwifruits was monitored directly on the intact fruit measuring the T(2) spin-spin relaxation time by means of a portable unilateral NMR instrument, fully non-invasive. Again, clear trends of the relaxation time were observed during the monitoring period. The results show that the monitoring of the metabolic profiling and the monitoring of the water status are two complementary means suitable to have a complete view of the investigated fruit.

NMR methodologies in the analysis of blueberries.

An NMR analytical protocol based on complementary high and low field measurements is proposed for blueberry characterization. Untargeted NMR metabolite profiling of blueberries aqueous and organic extracts as well as targeted NMR analysis focused on anthocyanins and other phenols are reported. Bligh‐Dyer and microwave‐assisted extractions were carried out and compared showing a better recovery of lipidic fraction in the case of microwave procedure. Water‐soluble metabolites belonging to different classes such as sugars, amino acids, organic acids, and phenolic compounds, as well as metabolites soluble in organic solvent such as triglycerides, sterols, and fatty acids, were identified. Five anthocyanins (malvidin‐3‐glucoside, malvidin‐3‐galactoside, delphinidin‐3‐glucoside, delphinidin‐3‐galactoside, and petunidin‐3‐glucoside) and 3‐O‐α‐l‐rhamnopyranosyl quercetin were identified in solid phase extract. The water status of fresh and withered blueberries was monitored by portable NMR and fast‐field cycling NMR. 1H depth profiles, T2 transverse relaxation times and dispersion profiles were found to be sensitive to the withering.

Metabolic profiling and outer pericarp water state in Zespri, CI.GI, and Hayward kiwifruits.

The metabolic profiling of aqueous extracts of Zespri Gold ( Actinidia chinensis ) and CI.GI (a controlled crossbreed from different species of Actinidia deliciosa ) kiwifruits and the water state of the outer pericarp of entire fruits were monitored over the season by means of high-field NMR spectroscopy and T(2) relaxation time measurements, respectively, and compared with the corresponding ones of Hayward kiwifruits previously investigated. A more complete assignment of the (1)H spectrum with respect to that obtained previously was reported: histidine, phenylalanine, quercetin 3-rhamnoside, and epicatechin were identified. Metabolic profiling confirmed Zespris earlier maturation compared with the two other varieties. The water state of entire kiwifruits was measured nondestructively on fruits attached to the plants or detached from the plants. T(2) relaxation times were found to be sensitive to the kiwifruit developmental stage.

Untargeted NMR-Based Methodology in the Study of Fruit Metabolites

In this review, fundamental aspects of the untargeted NMR-based methodology applied to fruit characterization are described. The strategy to perform the structure elucidation of fruit metabolites is discussed with some examples of spectral assignments by 2D experiments. Primary ubiquitous metabolites as well as secondary species-specific metabolites, identified in different fruits using an untargeted 1H-NMR approach, are summarized in a comprehensive way. Crucial aspects regarding the quantitative elaboration of spectral data are also discussed. The usefulness of the NMR-based metabolic profiling was highlighted using some results regarding quality, adulteration, varieties and geographical origin of fruits and fruit-derived products such as juices.

Evaluation of commercial compost quality

Ten commercial composts were evaluated on the basis of chemical, physical and biological characteristics and compared with a compost produced by a safe matrix in controlled conditions. FT-IR spectra, 13C CP-MAS NMR spectra and molecular weights were also assayed on humic acids extracted from the composts. The results show that the origin of the starting materials affects the quality of the end products especially for their heavy metal content and genotoxic effect. The presence of a high percentage of low molecular weight fractions generally recorded in the humic acids from commercial composts could be due to uncorrected composting process. FT-IR and 13C CP-MAS NMR spectra agree with functional group assignments, characterising the level of humification. The results show that commercial composts can display harmful properties probably due to the origin of the starting material, therefore a regulation about both compost production and characterisation should be suitable.

Xylem morphology determines the drought response of two Arundo donax ecotypes from contrasting habitats

Arundo donax exhibits rapid growth and requires little nutrient input, making it an ideal perennial biomass crop species. However, this growth is accompanied by high rates of water use, potentially restricting the use of A. donax in rain‐fed marginal lands. Here, we investigated the physiological and morphological responses to drought in two ecotypes of A. donax from contrasting habitats: one from an arid environment in Morocco, and the second from a warm humid sub‐Mediterranean climate in central Italy. Prolonged drought resulted in identical reductions in leaf‐level photosynthesis (PN) and stomatal conductance (Gs) in the two ecotypes. However, water deficit induced an increase in xylem vessel diameter in the Moroccan plants, improving the movement of water along the stem, but also likely reducing the resistance to embolism. In contrast, the Italian ecotype reduced xylem vessel area, thus increasing resistance to water transport and xylem embolism. The increased xylem vessel size and associated vulnerability to embolism in the Moroccan plants may have contributed to an increase in the loss of leaf numbers, but also to higher relative water content (RWC) in the remaining leaves in comparison to the Italian ecotype, where a greater number of leaves persisted. Despite the Moroccan plants possessing stems with a lower basal area than their Italian counterparts, both ecotypes exhibited identical leaf to supporting stem area ratios under both control and water deficit conditions. This may account for the similarities observed in leaf area measures of PN and Gs in this and previous studies of different A. donax ecotypes. Selection of A. donax ecotypes on the basis of xylem responses to drought may facilitate the development of varieties suited to arid environments prone to severe drought and wetter habitats where prolonged droughts occur less frequently.

Applications of Nuclear Magnetic Resonance Sensors to Cultural Heritage

In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported.