1,721,056 research outputs found
A method validation for simultaneous determination of phthalates and bisphenol A released from plastic water containers
Full text linkPhthalates (or phthalate esters, PAEs) and bisphenol A (BPA) are widely used in various industries, particularly in the fields of cosmetics and packaging, and they increase the malleability and workability of materials. As a result of their use, some international health organizations have begun to study them. In this study, the authors developed a methodology for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP); dibutyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP); di-n-octyl-phthalate (DnOP) and bisphenol A (BPA) from drinking and non-potable waters. The extraction of PAEs and BPA was performed using a solvent-based dispersive liquid-liquid microextraction (SB-DLLME) method. The analytical determination was performed using a gas chromatography-ion trap mass spectrometry (GC-IT/MS) analysis. The entire procedure was validated as recoveries were studied according to the volume and the extraction solvent used, pH, and ionic strength. Dynamic linearity ranges and linear equations of all the compounds were experimentally determined as well as the limit of detection (LOD) (1-8 ng mL-1) and the limit of quantification (LOQ) (5-14 ng mL-1), reproducibility, and sensitivity. The method was applied to 15 water samples (mineral water and tap water) for determining PAEs and BPA released from the plastic container. After the release simulation, four PAEs (i.e., DiBP, DBP, DHEP, and DnOP) were determined at very low concentrations (below 1.2 ng mL-1) in two water samples from (sport) bottles
Presenza di residui di farmaci ad uso umano e veterinario nelle acque potabili: revisione sistematica
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Phthalates and bisphenol-A determination and release from different beverage plastic containers by dispersive liquid-liquid microextraction and GC-IT/MS analysis
No full textPhthalates and bisphenol-A are molecules widely used in packaging because they increase the plastic malleability and workability but they show the tendency to migrate or dissociate from plastics. Recently, researchers raised the alarm to have found their traces in water samples of plastic bottles left at high outdoor temperatures for a long time. The paper would like to show a simple, sensitive, and reproducible method for the simultaneous determination of phthalates and bisphenol-A in drinking water, based on the dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry analysis. The dispersion is favored by means of ultrasonic bath and stirring magnetic plate, without dispersive solvent. The method presents an average R2 0.993 in the range 10–5000 ng mL-1, a limit of detection below 1.2 ng mL-1, and a limit of quantification below 7.7 ng mL-1. The release of such compounds from different beverage containers (6 plastic bottles, 6 canteens, and 3 newborn feeding bottles) has been analyzed. The release kinetics from the bottles are studied over 2 months, whereas over 6 h for the other containers. Only 2 compounds have been found in a plastic bottle and in a canteen bottle, with concentrations ranging between 24 and 117 ng mL-1
May SARS-CoV-2 diffusion be favored by alkaline aerosols and ammonia emissions?
Full text linkAmmonia is a common factor linking air in bat caves and air pollution in the proximity of agricultural fields treated with livestock farming sewage and slaughterhouses, where important clusters of COVID-19 have recently been reported all over the world. Such a commonality has a further connection with the known behavior of some viruses of the coronavirus family, such as the murine hepatitis virus, whose spike glycoprotein (S) can be triggered to a membrane-binding conformation at pH 8.0. Within the airborne route of virus transmission, with particular relevance for crowded and enclosed environments, these observations have prompted a hypothesis that may represent a contributing cause to interpret the geographical variability of the virus diffusion and the surging rise of COVID-19 cases in slaughterhouses all over the world. The hypothesis is that, in these environments, the SARS-CoV-2 S protein may find on a fraction of the airborne particles an alkaline pH, favorable to trigger the conformational changes, needed to induce the fusion of the viral envelope with the plasma membrane of the target cells
Valutazione dei livelli di particelle ultrafini emesse da sorgenti combustibili ed elettrodomestici mediante misure sperimentali
Full text linkRecenti studi hanno evidenziato che sorgenti combustibili di varia natura
quali candele, incensi e fumo di tabacco emettono durante l’utilizzo sia
sostanze che particelle fini e ultrafini potenzialmente dannose per la salute
umana. Inoltre, la qualità dell’aria degli ambienti confinati può essere
notevolmente peggiorata anche da altri elettrodomestici di uso comune, che
vengono utilizzati anche quotidianamente negli ambienti indoor di vita e
di lavoro. Scopo del lavoro è di valutare sperimentalmente l’inquinamento
indoor, in termini di livelli di particelle fini e ultrafini emesse durante
l’utilizzo di alcuni elettrodomestici e sorgenti combustibili di vario tipo
Passive vaping from sub-ohm electronic cigarette devices
Full text linkTo investigate passive vaping due to sub-ohm electronic cigarettes (e-cigs), aerosol number size distribution measurements (6 nm–10 μm) were performed during volunteer-vaping sessions. E-liquids, with vegetable glycerin (VG) and propylene glycol (PG), with a VG/PG ratio of 50/50 (with nicotine) and 80/20 (without nicotine), were vaped with a double-coil, single aerosol exit hole at 25–80 W electric power, corresponding to 130–365 kW m−2 heat fluxes and with an octa-coil, four aerosol exit holes atomizers, at 50–150 W electric power, corresponding to 133–398 kW m−2 heat fluxes. At the lowest heat flux, lower particle number concentrations (NTot ) were observed for the nicotine-liquid than for the nicotine-free liquid, also due to its higher content of PG, more volatile than VG. For the octa-coil atomizer, at 265 and 398 kW m−2, NTot decreased below the first-generation e-cig, whereas volume concentrations greatly increased, due to the formation of super micron droplets. Higher volume concentrations were observed for the 80/20 VG/PG liquid, because of VG vaporization and of its decomposition products, greater than for PG. For the double coil atomizer, increasing the electric power from 40 W (208 kW m−2 ) to 80 W (365 kW m−2 ) possibly led to a critical heat flow condition, causing a reduction of the number concentrations for the VG/PG 50/50 liquid, an increase for the 80/20 VG/PG liquid and a decrease of the volume concentrations for both of them. Coherently, the main mode was at about 0.1 μm on both metrics for both liquids. For the other tests, two main modes (1 and 2 μm) were observed in the volume size distributions, the latter becoming wider at 100 and 150 W (265 and 398 kW m−2 ), suggesting the increased emission of light condensable decomposition products. The lower aerosol emissions observed at 150 W than at 100 W suggest the formation of gas-phase decomposition products. The observation of low-count high-volume aerosols addresses the relevance of the volume metric upon measuring the second-hand concentration of the aerosols released by sub-ohm e-cigarettes
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