1,721,002 research outputs found
II) Wood pellets for home heating can be considered environmentally friendly fuels? Heavy metals determination by inductively coupled plasma-optical emission spectrometry (ICP-OES) in their ashes and the health risk assessment for the operators
No full textThe aim of the present study was to determine the concentrations of twelve potentially hazardous elements in wood pellet ashes obtained by the combustion of 13 pellet brands for sale in Italy, the impact of adding the ashes to soils and health risk of operator due to dust exposure. Samples were analysed by Inductively Coupled Plasma Optical Emission Spectrometry. The concentrations of heavy metals in ashes from stoves ranged from 0.41 to 7.2 mg kg-1 for As, from 1.3 to 12 mg kg-1 for Sb, from 1.8 to 12 mg kg-1 for Zn, from 0.23 to 0.8 mg kg-1 for Pb, from 0.18 to 2.8 mg kg-1 for Ni, from 0.09 to 1.0 mg kg-1 for Cd, from 0.46 to 3.4 mg kg-1 for Cr, from 0.94 to 2.7 mg kg-1 for V, from 2.2 to 11 mg kg-1 for Cu, from 60 to 409 mg kg-1 for Mn, from 83 to 432 mg kg-1 for Fe and from 3484 to 15,484 mg kg-1 for Al. The total concentrations for the 12 investigated elements, expressed as the sum of the concentrations (∑me), ranged from 3703 mg kg-1 to 15,946 mg kg-1 of dry weight with a mean of 8455 mg kg-1. Considering all the metals, the results indicate that there are very low risks for operators regarding non-carcinogenic and carcinogenic elements contained in the wood pellet ashes produced during cleaning of pellet stoves in confined environments
Critical evaluation of hazardous pollutants in edible insects: A simple review
Full text linkThe use of edible insects offers significant environmental benefits, particularly in terms of reducing greenhouse gas emissions and minimising water and land use. Recently, some species of edible insects have been recognised as novel foods in the European Union, regulated by Regulation (EU) 2015/2283 until the end of 2022. In this context, it is necessary to pay close attention to the assessment of the health risks posed by the contaminants ingested by insects. Indeed, there are numerous risks associated with the consumption of insects for human consumption. This review highlights the importance of assessing the health risks associated with contaminants in edible insects. Similar to other animal-derived foods, insects can accumulate hazardous substances such as heavy metals, pesticides, dioxins and flame retardants. This review aims to provide a comprehensive overview of contaminant levels in edible insects, based on studies published over the last two decades, in order to assess the potential health risks associated with their consumption
Titanium dioxide in face powders and eyeshadows: Developingan analytical methodology for accessing customer safety
Full text linkBackground: Titanium dioxide (TiO2 ), a white powder, represents the opacifier used inmany products, including drugs, foods, cosmetics, paints, and dyes.Method: The Uv-Vis spectrophotometry was a particularly suitable technique toquantify TiO2 in the solutions obtained from cosmetics. In this work, we determinedthe TiO2 content in a total of 88 samples of eye shadows and face powders of differ-ent brands and costs. Before to analyse the samples, we developed the mineralizationand analysis method, in fact, fusion with potassium bisulphate would be very labori-ous because it must be carried out on one sample at a time and requires very longtimes, instead, the mineralization with the acid mixture and the aid of microwavesallowed us to solubilize six samples at the same time within 45 min.Results: From the results obtained, we can state that the highest concentrations of TiO2 are found in the eyeshadows with a maximum value of 36% in a blue eyeshadow
A Short Review of Simple Analytical Methods for the Evaluation of PAHs and PAEs as Indoor Pollutants in House Dust Samples
Full text linkStudies on indoor air quality are indispensable when considering that people spend approximately 85% of their time in confined environments. This short review mostly takes into consideration research that uses passive samplers to evaluate the quality of indoor environments (houses, school, cars, etc.). This short review summarizes most analytical methods to detect and quantify PAHs and PAEs in house dust used as a passive sampler. The objective of house dust analysis is to identify the presence, amount and distribution of specific hazardous substances in confined spaces and, if possible, to identify their sources. Household dust and the compounds present in it can enter the human body by inhalation, non-food ingestion and absorption through the skin. The observed differences in concentrations of house dust may also indicate important differences in the chemical and physical nature of pollutants caused by air filtration and absorption during the migration of ambient air into the indoor environment
Analytical Method for Quantification of Several Phthalate Acid Esters by Gas Chromatography-Mass Spectrometry in Coffee Brew Samples
Full text linkSeveral phthalate acid esters (PAEs), often called phthalate esters or phthalates, are substances classified as harmful due to their carcinogenic and mutagenic properties, and moreover, as dangerous for humans because they interfere with the endocrine system. In general, phthalic esters are used as plasticizers for different polymers and more other consumer products. In the present study, we describe a simple method to quantify PAEs in coffee brew using a liquid-liquid extraction without purification processes through analysing the obtained organic phase by GCMS in the single ion monitoring mode. The totals of single PAEs, in coffee brew samples analysed by us, are in the range of 159-5305 mu g L-1. Considering that, on average, a person drinks three cups (total 90 mL) of the aforementioned drink per day, this will lead to the uptake of a total 14 to 477 mu g of phthalates
Voltammetry for Monitoring Platinum, Palladium and Rhodium in Environmental and Food Matrices
Full text linkThe interest of researchers on quantification of Pt, Pd and Rh in the environmental and food matrices is the consequence of the production of catalytic converters for car engines. Sensitization, mutagenic effects in bacterial and mammalian cells, and increased tumour incidence are the effects of Pt, Pd and Rh at high concentrations reported in medical and occupational researches while their effects at the low environmental concentrations have not been determined. Voltammetric techniques are very advantageous to quantify PGEs in environmental and food matrices due to their intrinsic sensitivity derived from the electrochemical pre-concentration of the analyte at the electrode surface, the capability to distinguish between different redox species and/or labile from non-labile metal complexes, with applications for metal speciation studies. The analysis of PGEs by spectrophotometric methods (atomic absorption, ICP-MS, ICP-OES, etc.) suffers from several practical problems. In this article we take into consideration the research concerning environmental and food matrices from 1996 to 2022
Il potenziale formale della coppia Ti(IV,III) a 25°C nel mezzo HCl 1 M NaCl 2 M
No full textNell’ambito delle diverse coppie ossidoriduttive di un elemento in soluzione acquosa, vengono indicate come ipoossidate le specie appartenenti a quelle coppie il cui potenziale standard è inferiore a quello di riduzione dell’acqua ad idrogeno, e come iperossidate le specie che fanno parte di coppie con valore del potenziale di riduzione superiore a quello dell’ossigeno ad acqua. Si tratta in entrambi i casi di specie termodinamicamente poco stabili che si trasformano rispettivamente nella forma ossidata con evoluzione di idrogeno e nella forma ridotta con evoluzione di ossigeno. Tali processi sono modulati dall’attività idrogenionica della soluzione (Figura 1).
Figura 1. Intervallo di stabilità termodinamica dell’acqua
La decomposizione di queste specie da parte dell’acqua, spesso catalizzata dagli stessi elettrodi metallici delle celle utilizzate per la misura dei potenziali redox, introduce una rilevante fonte di incertezza sulla composizione delle soluzioni; a questa si aggiunge l’incertezza dovuta alla presenza di giunzioni liquide, di impurezze nei mezzi ionici, alla mancanza di controllo dei coefficienti di attività. Tutto ciò ha come effetto le rilevanti differenze riscontrabili in letteratura tra i pochi valori riportati per i potenziali redox di tali sistemi.
Alcune di queste coppie con specie ipo o iperossidate (Ag2+, Co3+ , Ce4+ , Cr2+ , V2+, U3+ , Yb2+) sono state studiate nel nostro laboratorio e, i relativi valori dei potenziali redox in cui sono coinvolte, misurati [1-7]. Funzionale in questi studi è stata la diminuzione in alcuni casi della temperatura delle soluzioni (-5°C) così da ottenere una significativa attenuazione dell’azione di decomposizione esercitata dall’acqua.
Con riferimento a quanto appena detto, si è intrapreso lo studio della coppia redox (IV,III) del titanio, che nella forma di ione titanoso, Ti3+, in particolare sotto forma di cloruro o solfato, presenta numerose applicazioni analitiche [8]. D’altra parte, per le sue proprietà di elevata resistenza, il titanio metallico trova applicazioni tecnologiche che spaziano dalle leghe speciali, ai pigmenti bianchi, alla realizzazione di protesi ortopediche. Sulla base dell’esperienza acquisita, ci siamo proposti di determinare il potenziale redox della coppia Ti(IV, III), anche perché i valori riportati in soluzione acquosa per tale grandezza risultano notevolmente differenti [9-11].
L’indagine è stata effettuata con due metodi differenti: nel primo, per ottenere la miscela dei due stati di ossidazione, si è utilizzata l’ossidazione del Ti(III) a Ti(IV) per elettrolisi controllata (titolazioni coulombometriche) seguita dalla misura in situ della fem della cella senza giunzione
+ GE | Soluzione S | Hg - GE = Elettrodo a vetro
Nel secondo metodo, la specie ipoossidata Ti(III) è stata ottenuta per riduzione del Ti(IV) con amalgama di zinco (batch) seguita da determinazione potenziometrica, analoga alla precedente. Le due metodiche indipendenti hanno fornito valori del potenziale cercato in ottimo accordo, precisamente:
Metodo coulombometrico Ef = 9 + 1 mV
Metodo batch Ef = 9 + 2 mV
Riferimenti bibliografici
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2. Biedermann G, Orecchio S, Romano V, Zingales R. Acta Chem. Scand. 1986; A40:161
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6. Orecchio S, Piazzese D, Romano V, Zingales R. Ann. Chim. 1988; 88: 129
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11. Lingane J J Anal. Chem. 1958 20 79
Heavy Metals in Tattoo Inks: Developing an Analytical Methodology for Accessing Customer Safety
Full text linkTattoo inks contains metal salts or different types of coloured organic molecules. To the best of our knowledge, there are few data on the concentration of hazardous metals in tattoo inks sold online or by makeshift hawkers. The aim of this work was to organize an analytical methodology to ensure the simultaneous quantitative determination of 18 elements in a complex matrix, like inks for tattooing, by Inductively Coupled Plasma Mass Spectrometry. The total concentrations of metals in the 16 analysed tattoo ink samples ranged from 0.060 to 16.9 g kg(-1). Zinc is the most present metal in the samples, in fact it is in the range 3.4-13882 mg kg(-1). In three of the 16 samples the zinc concentrations exceed those required by legislation (2000 mu g g(-1)). Cr concentration in all cases is higher than allowed (0.5 mu g g(-1)). The weight loss by heating the ink samples to 105 degrees C and, subsequently, to 550 degrees C showed that in all cases the volatile component (ethanol, solvents, etc.) varies from 48 (Wh1) to 95 %, while the percentages of the residue at 550 degrees C ranged from 0 % (BK0) to 47 % (Wh1). Considering values limit, four of analysed samples should not be used by tattoo artists
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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