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1.
Molecules ; 28(2)2023 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-36677601

RESUMEN

Forest-based industries produce huge quantities of bark during their primary processing activities. In Nordic pulp and paper industries, where a wet debarking process is used for bark removal, toxic debarking water and bark press water are produced as a by-product. However, polyphenols represent an important fraction of the debarking water and bark press water. These polyphenolic compounds are of commercial interest in chemical specialty sectors since polyphenols have been proven to have diverse health benefits, and after collecting them from waste sources, they can act as alternatives to oil-based chemicals. Determining the economic potential of polyphenolic compounds, identifying their molecular structure, and determining the antioxidant capacity of these compounds present in debarking water and bark can support the identification of their potential applications. The results show that water extractions from bark have a lower efficiency than (partial) alcoholic extractions. Nevertheless, a considerable amount of low-molecular polyphenolic compounds, which are of interest for high-end applications, was found in all extracts. Bark press water has a highly versatile range of polyphenolic compounds and showed some antioxidant activity, making it a great source for the collection of polyphenolic compounds, in contrast to debarking water, which had a much lower polyphenolic content and low antioxidant activity.


Asunto(s)
Antioxidantes , Agua , Antioxidantes/química , Polifenoles/química , Extractos Vegetales/química
2.
Nanomaterials (Basel) ; 12(14)2022 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-35889552

RESUMEN

Olive mill waste water (OMWW), a by-product created during the processing of olive oil, contains high amounts of polyphenolic compounds. If put to further use, these polyphenolic compounds could be a valuable resource for the speciality chemical industry. In order to achieve this, isolation of the polyphenolic compounds from OMWW is needed. Several techniques for this process already exist, the most widely used of which is adsorption beds. This research describes new ways of collecting polyphenolic compounds by using unmodified iron oxide (Fe3O4) particles and Fe3O4 modified with silica gel (Fe3O4@C18), citric acid (Fe3O4@CA), and sodium dodecyl sulphate (Fe3O4@SDS). This approach is superior to adsorption beds since it can be used in a continuous system without clogging, while the nano-sized shapes create a high surface area for adsorption. The results of this study show that, if used in a loop system of several adsorption and desorption cycles, (un)modified Fe3O4 has the potential to collect high concentrations of polyphenolic compounds. A combination of different modifications of the Fe3O4 particles is also beneficial, as these combinations can be tailored to allow for the removal of specific polyphenolic compounds.

3.
Foods ; 11(6)2022 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-35327237

RESUMEN

Rapeseed meal and pressed cake are protein-rich by-products from rapeseed after oil extraction. Because of the high protein content, these by-products are an important source of food protein. Their use is motivated by the current pressure on protein prices, increasing demand for functional ingredients, and remaining controversy over wider use of soy. During process development for protein extraction from rapeseed cake or meal, special attention needs to be given to compounds such as erucic acid, which can cause problems if consumed in high amounts. Erucic acid determination is critical to ensure safety, since protein extraction procedures could lead to concentration of this compound in the final product. This research compared differences in extraction (Soxhlet and Folch) and derivatization techniques to obtain the highest erucic acid yield from rapeseed protein products. Results showed that no erucic acid accumulation occurred in the protein during its extraction from the rapeseed cake. The Soxhlet procedure was superior to Folch, as it yielded the highest concentrations of erucic acid. Furthermore, with the Folch procedure, some natural cis-configuration of erucic acid converted to its corresponding trans-configuration (brassidic acid). The latter is important, as ignoring this phenomenon can lead to underestimation of erucic acid content in rapeseed protein samples.

4.
Molecules ; 26(21)2021 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-34770812

RESUMEN

The conversion of raw fruits and vegetables, including tomatoes into processed food products creates side streams of residues that can place a burden on the environment. However, these processed residues are still rich in bioactive compounds and in an effort to valorize these materials in tomato by-product streams, the main aim of this study is to extract proteins and identify the main phenolic compounds present in tomato pomace (TP), peel and skins (TPS) by HPLC-DAD-ESI-QTOF. Forty different phenolic compounds were identified in the different tomato extracts, encompassing different groups of phenolic compounds, including derivatives of simple phenolic acid derivatives, hydroxycinnamoylquinic acid, flavones, flavonones, flavonol, and dihydrochalcone. In the crude protein extract (TPE) derived from tomatoes, most of these compounds were still present, confirming that valuable phenolic compounds were not degraded during food processing of these co-product streams. Moreover, phenolic compounds present in the tomato protein crude extract could provide a valuable contribution to the required daily intake of phenolics that are usually supplied by consuming fresh vegetables and fruits.


Asunto(s)
Manipulación de Alimentos , Fenoles/análisis , Extractos Vegetales/análisis , Proteínas de Plantas/química , Solanum lycopersicum/química , Cromatografía Líquida de Alta Presión , Espectrometría de Masas
5.
Molecules ; 26(22)2021 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-34834035

RESUMEN

Olive oil production using three-phase decanter systems creates olive oil and two by-products: olive mill wastewater (OMWW) and pomace. These by-products contain the highest share of polyphenolic compounds that are known to be associated with beneficial effects on human health. Therefore, they are an attractive source of phenolic compounds for further industrial use in the cosmetic, pharmaceutical and food industries. The use of these phenolics is limited due to difficulties in recovery, high reactivity, complexity of the OMWW matrix and different physiochemical properties of phenolic compounds. This research, focused on OMWW, was performed in two phases. First, different polyphenol extraction methods were compared to obtain the method that yields the highest polyphenol concentration. Twenty-five phenolic compounds and their isomers were determined. Acidifying OMWW, followed by five minutes of ultrasonication, resulted in the highest measured polyphenol content of 27 mg/L. Second, the collection of polyphenolic compounds from OMWW via adsorption on unmodified iron (II, III) oxide particles was investigated. Although low yields were obtained for removed polyphenolic compounds in one removal cycle, the process has a high capability to be repeated.


Asunto(s)
Óxido Ferrosoférrico/química , Residuos Industriales , Olea , Polifenoles/química , Aguas Residuales/química , Purificación del Agua , Humanos , Eslovenia
6.
Plants (Basel) ; 10(11)2021 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-34834911

RESUMEN

Glucosinolates are well known as natural antimicrobials and anticarcinogenic agents. However, these compounds can lose their properties and transform into antinutrients, depending on processing conditions. In addition, the bitterness of some glucosinolate in rapeseed meal can affect the likability of the final product. Therefore, it is important to identify and determine each glucosinolate and its derived form, not just the total glucosinolate content, in order to evaluate the potential of the final rapeseed protein product. This study provides a comprehensive report of the types and quantities of glucosinolates and their derived forms (isothiocyanates) associated with different rapeseed processing conditions. Glucosinolates and isothiocyanates were determined by HPLC-DAD-qTOF. In our study, the enzymatic degradation of glucosinolates by myrosinase was the main factor affecting either glucosinolate or isothiocyanate content. Other factors such as pH seemed to influence the concentration and the presence of glucosinolates. In addition, process parameters, such as extraction time and separation technology, seemed to affect the amount and type of isothiocyanates in the final protein extracts. Overall, both determined intact glucosinolates and their derived forms of isothiocyanates can give different types of biological effects. More studies should be performed to evaluate the impact of glucosinolates and isothiocyanates on human health.

7.
Plants (Basel) ; 10(8)2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34451560

RESUMEN

Helichrysum italicum is an aromatic plant with promising pharmacological activities. Bioactive compounds found in plants represent an important alternative treatment for weight loss and an infusion of H. italicum contains compounds which could have such effect. Our aim was, therefore, to investigate its acute effects on resting energy expenditure (REE) and possible differences in substrate oxidation in a pilot study. A dried, ground plant material of H. italicum ssp. italicum was infused with hot water and chemically characterized with HPLC-MS analysis. Sensory evaluation of herbal tea was performed. A randomized, crossover, controlled pilot study was then conducted on eleven healthy male subjects. The REE and substrate oxidation were measured by indirect calorimetry at baseline and 30 and 120 min after ingestion of infusion or hot water. The expression of genes involved in lipid metabolism was examined in H. italicum infusion-treated hepatocytes. Several phenolic classes were identified in the infusion, caffeoylquinic acids were the most abundant, followed by pyrones and flavonols. A single ingestion of H. italicum infusion significantly increased REE by 4% and fat oxidation by 12% compared to hot water ingestion. A significant 2-fold up-regulation of ß-oxidation-related genes in HepG2 cells, exposed to H. italicum infusion, was detected. This pilot study suggests that H. italicum infusion possesses bioactive substances with potential application in obesity prevention, which could, with additional studies, become an economically interesting novel application of the plant. Clinical trial registration number: NCT04818905.

8.
Molecules ; 26(1)2020 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-33375027

RESUMEN

The valorization of olive pomace through the extraction of phenolic compounds at an industrial scale is influenced by several factors that can have a significant impact on the feasibility of this approach. These include the types and levels of phenolic compounds that are present, the impact that seasonal variation and cultivar type have on the phenolic compound content in both olive pomace and mill effluents and the technological approach used to process the olive crop. Chemical analysis of phenolic compounds was performed using an HPLC-diode-array detector (DAD)-qTOF system, resulting in the identification of 45 compounds in olive mill wastewater and pomace, where secoiridoids comprised 50-60% of the total phenolic content. This study examined three different factors that could impact the phenolic compound content of these processing streams, including cultivar types typically grown on local farms in Slovenia, the type of downstream processing used and seasonality effects. Olive crop varieties sourced from local farms showed high variability, and the highest phenolic content was associated with the local variety "Istrska Belica". During processing, the phenolic content was on average approximately 50% higher during two-phase decanting compared to three-phase decanting and the type of compound present significantly different. An investigation into the seasonal effects revealed that the phenolic content was 20% higher during the 2019 growing season compared to 2018. A larger sample size over additional growing seasons is required to fully understand the annual variation in phenolic compound content. The methods and results used in this study provide a basis for further analysis of phenolic compounds present in the European Union's olive crop processing residues and will inform techno-economic modelling for the development of olive biorefineries in Slovenia.


Asunto(s)
Olea/química , Fenoles/química , Fenoles/aislamiento & purificación , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Aguas Residuales/química , Fraccionamiento Químico/métodos , Cromatografía Líquida de Alta Presión , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/aislamiento & purificación , Depuradores de Radicales Libres/farmacología , Estructura Molecular , Olea/crecimiento & desarrollo , Fenoles/farmacología , Extractos Vegetales/farmacología , Estaciones del Año , Eslovenia
9.
Sci Rep ; 10(1): 18961, 2020 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-33144608

RESUMEN

Fires can have a negative impact on the environment, human health, property and ultimately also on various objects of cultural heritage (CH). This paper deals with an investigation into the degradation of selected proteinaceous paint layers that were exposed to fire-related effects (i.e., fire effluents and/or high temperatures) in a modified cone-calorimeter system. Paint layers of egg yolk adhesive (E) and lead white tempera (E + LW) were exposed to fire-related impacts on top of a CH stack and in a specially designed CH test chamber. On the CH stack, the proteinaceous paint layers were exposed to fire effluents and high temperatures, while in the CH test chamber, the samples were exposed mainly to fire effluents. The molecular changes to the exposed paint layers were analysed by invasive and non-invasive spectroscopic analyses (i.e., FTIR and Raman spectroscopy) and complimented with pyrolysis-GC-MS, while the colour changes were evaluated using colourimetry. It was concluded that the proteinaceous binder degrades into aromatic amino acids and/or fatty acids after exposure to the overall impacts of the fire. Aromatic amino acids were detected by means of the FTIR and py-GC-MS analyses. In the case of the lead white tempera exposure, partial dissociation of the lead white pigment was confirmed by the detection of alteration products, such as lead oxide and lead carbonate. Moreover, the investigation of the E + LW samples exposed for longer times revealed the presence of lead carboxylates. On the other hand, no significant molecular changes were observed with the CH samples exposed to fire effluents in the CH test chamber. The research offered us an insight into the fire-induced effects on selected paints for the first time.

10.
Metabolites ; 10(10)2020 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-33053777

RESUMEN

Mediterranean plant Helichrysum italicum represents a rich source of versatile bioactive compounds with potential benefits for human health. Despite extensive research on the plant's active constituents, little attention has yet been paid to characterizing the relationship between its intra-specific genetic diversity and metabolite profile. The study aimed to determine metabolic profile of H. italicum ssp. italicum (HII) and ssp. tyrrhenicum (HIT) cultivated on the experimental plantation in Slovenia and to compare the chemical composition of extracts regarding the solvent extraction process. Extracts were prepared upon conventional extract preparation procedures: maceration with 50 % methanol or ethanol and cold or hot water infusion and analyzed using High Performance Liquid Chromatography-Diode Array Detection-Electrospray Ionization-Quadrupole Time-of-Flight-Mass Spectrometry (HPLC-DAD-ESI-QTOF-MS). One hundred compounds were identified in the samples, among them several isomers and derivatives were reported for the first time, while caffeoylquinic acids and pyrones were the most abundant. Semi-quantitative comparison revealed that the extraction procedure had a greater impact on the chemical profile than genetic variability. All HIT extracts showed a higher total phenolic content compared to HII, while the antioxidant potential evaluated by 1,1-diphenyl-2-picrylhydrazil test was not proportionally higher. In addition, hot water extracts proved to be comparably active as alcoholic ones, confirming high commercial potential of Helichrysum italicum as herbal functional beverages.

11.
Food Chem ; 230: 327-335, 2017 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-28407918

RESUMEN

Nickel (Ni) is considered to be a potentially harmful element for humans. Its levels in foodstuffs are normally low (below 0.2mgkg-1), but sensitive individuals may develop allergy to Ni as a result of dietary consumption. Cocoa contains relatively high Ni concentrations (around 3mgkg-1). Ni bioavailability, its role in the flavour of food and its potential impact on human health depends primarily on its chemical species. However, there is a lack of information about Ni speciation in cocoa. In this work Ni species were separated on a weak convective interaction media diethylamine (CIM DEAE) monolithic chromatographic column and quantified by the post-column isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). The Ni binding ligands in the separated fractions were identified "off line" by quadrupole time-of-flight mass spectrometry (Q-TOF MS). Ni was found to be present in the cocoa infusions as Ni2+ and Ni-gluconate and Ni-citrate complexes.


Asunto(s)
Chocolate/análisis , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas/métodos , Níquel/química , Análisis Espectral/métodos , Humanos , Níquel/análisis
12.
Water Res ; 94: 315-327, 2016 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-26971807

RESUMEN

Among the different nanoparticles (NPs) that are used in the remediation of contaminated environmental waters, iron nanoparticles (FeNPs) are the most frequently applied. However, if these FeNPs remain in the waters after the treatment, they can cause a hazard to the environment. In this work the time dependent size distribution of iron particles was investigated in Milli-Q water, forest spring water and landfill leachate after a variety of FeNP treatments. The efficiency of the metal removal by the FeNPs was also examined. The concentrations of the metals in the aqueous samples were determined before and after the nano-remediation by inductively coupled plasma mass spectrometry (ICP-MS). The data revealed that the settling and removal of the FeNPs after the treatment of the waters was related to the sample characteristics and the ways of dispersing the NPs. When mixing was used for the dispersion, the nano zero-valent iron (nZVI), FeONPs and Fe3O4NPs settled quickly in the Milli-Q water, the forest spring water and the landfill leachate. Dispersion with tertramethylammonium hydroxide (TMAH) resulted in a slower settling of the iron aggregates. In the Milli-Q and forest spring waters treated with FeONPs and dispersed by TMAH, the nanosized iron remained in solution as long as 24 h after the treatment and could represent a potential threat in environmental waters with a low ionic strength. The removal of the metals strongly depended on the type of FeNPs, the chemical speciation of the elements and the sample matrix. If the FeNPs are contaminated by a particular metal, this contaminant could be, during the NPs treatment, released into the water that is being remediated.


Asunto(s)
Hierro/análisis , Nanopartículas del Metal/análisis , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Monitoreo del Ambiente , Agua Subterránea/análisis , Compuestos de Amonio Cuaternario/análisis , Agua/análisis
13.
Viral Immunol ; 29(3): 169-75, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27002465

RESUMEN

Morbidity and mortality in the elderly are associated with viral infections, including influenza and cytomegalovirus (CMV). With increasing age, cellular immunity gains importance in protection to influenza, but latent CMV is highly prevalent and associated with immune dysfunction. An insight into the association between immunity against influenza and CMV adds to the understanding of healthy aging. Here we first aimed to measure influenza-specific cellular immunity using granzyme B (GrzB) and interferon-gamma (IFN-γ)-ELISpot. Next, influenza-specific cellular immunity was associated with humoral and cellular CMV-specific immunity in healthy 65+ elderly. Vaccine trial participants gave additional blood samples 3 weeks after receiving a H1N1 containing vaccine. CMV serology was determined and peripheral blood mononuclear cells were stimulated with influenza N1 or CMV pp65-derived peptide pools for 7 days and rechallenged to assess antigen-specific GgrzB and IFN-γ responses using ELISpot assays. Results were compared using chi-square and correlation analysis. Eighty-three individuals (60% men, 65% CMV IgG+, age range 65-78y) participated. We found significant positive associations between IFN-γ and GrzB responses to both influenza and CMV, but also between a positive CMV serostatus and an influenza N1-specific activation marker response (p = 0.013). CMV pp65 responses were detected in CMV IgG+ individuals, but remarkably also in CMV IgG- individuals (27%). In this study, following influenza vaccination, elderly with cellular immunity against CMV were more likely to have cellular immunity against influenza vaccine N1 antigen. These findings stress the need to continue exploring the possible role of CMV in immunosenescence.


Asunto(s)
Antígenos Virales/inmunología , Citomegalovirus/inmunología , Granzimas/inmunología , Gripe Humana/inmunología , Interferón gamma/inmunología , Neuraminidasa/inmunología , Fosfoproteínas/inmunología , Proteínas de la Matriz Viral/inmunología , Proteínas Virales/inmunología , Anciano , Envejecimiento/inmunología , Anticuerpos Antivirales/sangre , Infecciones por Citomegalovirus/inmunología , Infecciones por Citomegalovirus/mortalidad , Infecciones por Citomegalovirus/virología , Femenino , Humanos , Inmunidad Celular/inmunología , Subtipo H1N1 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Gripe Humana/virología , Masculino , Vacunación
14.
Environ Res ; 142: 511-21, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26280471

RESUMEN

Biotic and abiotic degradation of toxic organotin compounds (OTCs) in landfill leachates is usually not complete. In this work adsorption and degradation processes of tributyltin (TBT) and trimethyltin (TMeT) in leachate sample treated with different iron nanoparticles (FeNPs): Fe(0) (nZVI), FeO and Fe3O4 were investigated to find conditions for their efficient removal. One sample aliquot was kept untreated (pH 8), while to the others (pH 8) FeNPs dispersed with tetramethyl ammonium hydroxide (TMAH) or by mixing were added and samples shaken under aerated conditions for 7 days. The same experiments were done in leachates in which the pH was adjusted to 3 with citric acid. Size distribution of TBT and TMeT between particles >5 µm, 0.45-5 µm, 2.5-0.45 µm, and <2.5 nm was determined by sequential filtration and their concentrations in a given fraction by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS). Results revealed that most of the TBT or TMeT was present in fractions with particles >2.5 or <2.5 nm, respectively. At pH 8 adsorption of TBT to FeNPs prevailed, while at pH 3, the Fenton reaction provoked degradation of TBT by hydroxyl radicals. TBT was the most effectively removed (96%) when sequential treatment of leachate with nZVI (dispersed by mixing) was applied first at pH 8, followed by nZVI treatment of the aqueous phase, previously acidified to pH 3 with citric acid. Such treatment less effectively removed TMeT (about 40%). It was proven that TMAH provoked methylation of tin, so mixing was recommended for dispersion of nZVI.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Peróxido de Hidrógeno/química , Hierro/química , Nanopartículas de Magnetita/química , Compuestos de Trialquiltina/análisis , Compuestos de Trimetilestaño/análisis , Contaminantes Químicos del Agua/análisis , Adsorción , Monitoreo del Ambiente , Cromatografía de Gases y Espectrometría de Masas , Límite de Detección , Reproducibilidad de los Resultados , Espectrofotometría Atómica , Compuestos de Trialquiltina/química , Compuestos de Trimetilestaño/química , Contaminantes Químicos del Agua/química
15.
J Immunol ; 193(10): 4952-61, 2014 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-25305322

RESUMEN

The lytic function of CTL relies on the polarized release of cytotoxic granules (CG) at the immune synapse (IS) with target cells. CTL also contain CCL5 in cytoplasmic storage vesicles (CCL5V) distinct from CG, the role of which, in regulating T cell effector functions, is not understood. Using human CD8(+) T cells specific to a lung tumor-associated Ag, we show in this article that CTL release both secretory compartments into the immune synapse with autologous tumor cells. Moreover, we demonstrate that disorganization of the T cell microtubule cytoskeleton and defects in hMunc13-4 or Rab27a abrogate CG exocytosis and synaptic secretion of the chemokine. Mechanistically, synaptic release of CCL5 cytoplasmic storage vesicles likely occurs upon their coalescence with the Rab27a-hMunc13-4 compartment and results in autocrine, CCR5-dependent induction of CXCR4 cell surface expression, thereby promoting T cell migration in response to CXCL12. We propose that CCL5 polarized delivery represents a mechanism by which CTL control immune synapse duration.


Asunto(s)
Antígenos de Neoplasias/inmunología , Quimiocina CCL5/inmunología , Quimiocina CXCL12/inmunología , Citotoxicidad Inmunológica , Receptores CXCR4/inmunología , Linfocitos T Citotóxicos/inmunología , Antígenos de Neoplasias/genética , Línea Celular Tumoral , Quimiocina CCL5/genética , Quimiocina CCL5/metabolismo , Quimiocina CXCL12/genética , Quimiotaxis , Gránulos Citoplasmáticos/química , Gránulos Citoplasmáticos/inmunología , Exocitosis/inmunología , Regulación de la Expresión Génica , Humanos , Sinapsis Inmunológicas , Microtúbulos/inmunología , Proteínas del Tejido Nervioso/deficiencia , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/inmunología , Receptores CXCR4/genética , Transducción de Señal , Linfocitos T Citotóxicos/patología , Proteínas de Unión al GTP rab/deficiencia , Proteínas de Unión al GTP rab/genética , Proteínas de Unión al GTP rab/inmunología , Proteínas rab27 de Unión a GTP
16.
Water Res ; 53: 297-309, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24530549

RESUMEN

Landfill leachates are an important pool of organotin compounds (OTCs). Several studies have been performed on the occurrence of OTCs in landfill leachates, but only a few of them report degradation and biomethylation processes by bacteria. In the present study transformation of OTCs in landfill leachate was investigated under simulated landfill conditions over a time span of six months. The degradation and biomethylation processes of OTCs were followed by the use of isotopically enriched tin tracers, namely (117)Sn-enriched tributyltin (TBT), (119)Sn-enriched dibutyltin (DBT), (117)Sn-enriched SnCl2, (117)Sn-enriched SnCl4 and a (119)Sn-enriched butyltin mix containing TBT, DBT and monobutyltin (MBT). Transformation of OTCs in spiked leachates was followed at m/z of the enriched spikes and at m/z 120, which allowed simultaneous observation of the transformation of OTCs in the leachate itself and of the added spike. In parallel, these processes were also monitored in a non-spiked leachate sample at m/z 120. Quantification of OTCs was performed by gas chromatography - inductively coupled plasma mass spectrometry (GC-ICP-MS). To discriminate the biotic and abiotic transformations of OTCs and inorganic tin species, sterilization of leachate was also performed and data compared to non-sterilized samples. During the course of the experiment the microbial degradation of TBT was clearly manifested in Sn-enriched spiked leachate samples, while abiotic pathway of degradation was observed for DBT. Biomethylation process was also observed in the leachate spiked with Sn-enriched Sn(2+) or Sn(4+), in concentrations close to those found for total tin in landfill leachates. Monomethyltin (MMeT) was formed first. Stepwise alkylation resulted in dimethyltin (DMeT) and trimethyltin (TMeT) species formation. Hydrolysis of Sn(2+) and Sn(4+) species was found to be a limiting factor which controlled the extent of methyltin formation. The results of the present investigation importantly contribute to a better understanding of the processes that OTCs undergo in leachates, and provide useful information to managers of landfills in taking measures necessary to prevent the release of toxic methyltin species to the nearby environment.


Asunto(s)
Monitoreo del Ambiente , Contaminantes Ambientales/química , Compuestos Orgánicos de Estaño/química , Estaño/química , Contaminantes Químicos del Agua/química , Contaminantes Ambientales/análisis , Cromatografía de Gases y Espectrometría de Masas , Isótopos/química , Compuestos Orgánicos de Estaño/análisis
17.
Chemosphere ; 107: 386-392, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24472491

RESUMEN

Organotin compounds (OTCs) are among the most toxic substances ever introduced to the environment by man. They are common pollutants in marine ecosystems, but are also present in the terrestrial environment, accumulated mainly in sewage sludge and landfill leachates. In investigations of the degradation and methylation processes of OTC in environmental samples, the use of enriched isotopic tracers represents a powerful analytical tool. Sn-enriched OTC are also necessary in application of the isotope dilution mass spectrometry technique for their accurate quantification. Since Sn-enriched monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) are not commercially available as single species, "in house" synthesis of individual butyltin-enriched species is necessary. In the present work, the preparation of the most toxic butyltin, namely TBT, was performed via a simple synthetic path, starting with bromination of metallic Sn, followed by butylation with butyl lithium. The tetrabutyltin (TeBT) formed was transformed to tributyltin chloride (TBTCl) using concentrated hydrochloric acid (HCl). The purity of the synthesized TBT was verified by speciation analysis using the techniques of gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) and nuclear magnetic resonance (NMR). The results showed that TBT had a purity of more than 97%. The remaining 3% corresponded to DBT. TBT was quantified by reverse isotope dilution GC-ICP-MS. The synthesis yield was around 60%. The advantage of this procedure over those previously reported lies in its possibility to be applied on a micro-scale (starting with 10mg of metallic Sn). This feature is of crucial importance, since enriched metallic Sn is extremely expensive. The procedure is simple and repeatable, and was successfully applied for the preparation of (117)Sn-enriched TBTCl from (117)Sn-enriched metal.


Asunto(s)
Técnicas de Química Sintética/métodos , Contaminantes Ambientales/química , Contaminantes Ambientales/síntesis química , Cromatografía de Gases y Espectrometría de Masas , Estaño/química , Compuestos de Trialquiltina/química , Compuestos de Trialquiltina/síntesis química , Estabilidad de Medicamentos , Contaminantes Ambientales/análisis , Isótopos , Espectroscopía de Resonancia Magnética , Compuestos Orgánicos de Estaño/química , Reproducibilidad de los Resultados , Compuestos de Trialquiltina/análisis
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