M. Bosetto

Quantitative Determination of Some Essential Oil Components of Selected Artemisia absinthium Plants

ABSTRACT The essential oils obtained by steam distillation of leaves and flowers of 49 selected Artemisia absinthium mother plants of different geographical origins which were grown in Tuscany (Carmignano, Firenze), were analyzed by GC. More than 90 compounds were found in the oils, most of which occurred only in trace amounts. Eight components, which have been reported to have antibacterial activity (α- and β-thujone, terpinen-4-ol, linalool, nerol, geraniol, α-pinene, 1,8-cineole) were identified and their percentages in each of the oils were determined. From these results, oil composition variations both within and between the accessions were found. Some genotypes were characterized by particularly high percentages of active principles.

Study of the Maillard reaction products formed by glycine and D-glucose on different mineral substrates

Abstract This work deals with the formation of humic-like compounds, products of the Maillard reaction between glycine and D-glucose, on clay (K+, Ca2+ and Al3+-saturated montmorillonite and kaolinite) and quartz systems in the presence of the same cations. Natural quartz was used as the control while the effect of cation type, mineral substrate and CEC was evaluated. All the systems form humic-like substances that are probably responsible for the decrease in the pH (H2O) after 30 d. The type of cation does not influence the overall production of humic substances, while the amount of cations controls the formation of humic-like material especially in the presence of clays. A mineral surface is necessary to synthesize molecules with this high degree of complexity. Fulvic-like compounds are produced in great amounts on natural quartz and their formation is hampered by the presence of ‘free’ cations, regardless of their amount. Humic substances do not penetrate the interlayer of montmorillonite.

Humic-like compounds formed from l-tryptophan and d-glucose in the presence of CU (II)

Abstract This study concerns the humic-like polymeric compounds formed by D-glucose plus L-tryptophan and by L-tryptophan alone, both on Cu-saturated nontronite, montmorillonite and kaolinite and on quartz in the presence of Cu(II) ions. These mineral-organic systems were kept in thermostat at 70°C for 30 days and submitted to alternate wetting-drying cycles. Higher amounts of humic-like compounds were extracted from quartz-organic than from clay-organic systems, showing the remarkable action of Cu(II), which even overcame the high catalytic power of clays.

Interactions of two acetanilide herbicides with clay surfaces modified with Fe(III) oxyhydroxides and hexadecyltrimethyl ammonium

Abstract The adsorption at 22° and 5°C of two acetanilide herbicides (Alachlor and Metolachlor) on montmorillonite saturated with HDTMA+ cation or coated with Fe(III) oxyhydroxides (modified clays) was studied. The isotherms were of L, S and C type depending on the type of the adsorbent. The calculated values of isosteric adsorption heat (ΔH) and desorption experiments suggest that weak bonds take place. FT-IR analyses showed that both molecules are adsorbed on clays by hydrogen bond between the C-O group and OH groups of Fe(III) oxyhydroxy cation coating the clay. Also on HDTMA-Montmorillonite the C-O group is involved in the adsorption but with lower strenght. Alachlor is only partially decomposed to 2-chloro-2′,6′-diethylacetanilide when the dirty clays complexes are heated at 70°C for 18 h. X-ray analyses showed that both herbicides were unable to penetrate into the inter-layers of the clays.

Synthesis and Characterization of Maillard Compounds Formed under Sterile Conditions on Sand‐ and Silt‐Sized Mineral Substrates

Abstract Maillard compounds were synthesized from D‐glucose and glycine to mimic the separation of particles during a volcanic eruption so that the role of quartz and volcanic ash, fractionated into silt‐ and sand‐size particles, could be tested under sterile conditions. The obtained polymers were separated into two fractions of 1000–8000 and >8000 Daltons. The results evidence the formation of humus‐like polymers from simple compounds and show the importance of substrate mineralogy. Specifically, a) humic‐like polymers can form in the absence of microbial life, b) the role of particle size is important, c) mineral substrates enhance their yields, d) the polymers on volcanic ash and quartz show differences, e) their structure changes with time, f) at the end of the experiments there is an increase of unsaturation while the aliphaticity decreases, and g) the yields of the compounds of 1000–8000 Daltons decrease with time unlike those >8000.

Synthesis of Humic-like Substances Under Sterile and Non-sterile Conditions in Presence of Quartz and Volcanic Ash

This study reports on the formation of Maillard compounds (humic-like substances called “melanoidins”) from D-glucose and L-tyrosine in the presence of volcanic ash and pure quartz. It was demonstrated that the synthesis occurred not only under non-sterile, but also under sterile conditions, and under moisture and temperature stress. The temperature remained for 30 days at 70°C for 63% of the time. The non-sterile environment with a contact time of at least 30 days was the most favorable condition for the synthesis. In sterile environment, only low molecular weight polymers were formed, while in non-sterile systems high molecular weight substances were synthesized. The presence and the nature of mineral substrates appeared important even if not essential for the formation of humic-like substances. In fact, these substances were also formed by the reaction of the precursors alone.

Characterization of the Soil Organic Matter in Agricultural Mine Spoils and Reclaimed Soils Treated with Organic Amendments

Recycling organic waste in agricultural soils is a valid solution. We performed short‐term experiments to investigate the fate of urban sludge and composts, in mine spoils, cultivated or uncultivated, and reclaimed soils located in Florence and Milan, Italy. The samples, either treated or untreated, were fractionated by density into light (<1.63 Mg m−3) and heavy (>1.63 Mg m−3) fractions. The fractions were analyzed for total carbon (C) and nitrogen (N) contents and for δ 13C and δ 15N isotopes, and they were characterized by 13C NMR spectroscopy. Treatment increased the heavy fraction. The addition of sludge in the Florence area acts in synergy with the cultivation, increasing the light fraction (LF). In the Milan area, the LF tends to be decomposed and apparently transformed into HF. The addition of amendments or cultivation enhances the decomposition with release of carbon dioxide. For future research, we suggest lengthening the time of the experiments to integrate climatic variations.