Lung-deposited surface area concentration measurements in selected occupational and non-occupational environments

AbstractPrevious experimental and epidemiologic studies suggested that exposure to ultrafine particles (UFP) may result in adverse health effects. Metrics such as the number-concentration and especially the surface-area or lung-deposited surface area (LDSA) appear to be appropriate metrics of dose for predicting pulmonary inflammation of insoluble and poorly soluble ultrafine particles. Currently not much data including LDSA concentrations is available. The aim of this study was therefore to measure LDSA concentrations in a variety of occupational and non-occupational environments as well as in chamber tests. To this end, novel handheld online-monitors were deployed and evaluated for their suitability to be used in a variety of micro-environments and under different conditions. Chamber emissions tests included incense and candle burning, 3D printing and cigarette/e-cigarette smoking. The LDSA concentration was measured in occupational environments such as a canteen kitchen, a welding workshop and in a car. Measurements were also conducted in a private house with a wood-burning stove and with ongoing parallel cooking activities. Depending on the type of micro-environment, the ongoing activities or the material investigated in the chamber-tests, large differences were observed in terms of measured LDSA concentrations, some exceeding up to 1000 times that of the baseline concentration detected before activities initiated. In some of the investigated environments LDSA concentrations were measured for the first time. The data might therefore serve as reference for future studies. The handheld instrument used to measure this data worked well both for stationary measurements as well as for personal monitoring and proved to be an alternative to bulkier benchtop instruments

Desarrollo, evaluación y caracterización de Fases Reactivas, sensibles a diferentes analitos y su empleo en sensores ópticos en flujo

El objeto fundamental de la presente memoria se ha centrado en la evaluación de diferentes "terminales sensibles" a los analitos hierro y aluminio con el fin de seleccionar los mas adecuados para el desarrollo de sensores ópticos en flujo, de fluorescencia y de reflectancia. En todos los sensores desarrollados se ha seguido la misma sistemática de trabajo: construcción de la fase sensible al analito a determinar (elección del reactivo, soporte y proceso de inmovilización); diseño y optimización del sistema de medida; caracterización de la fase reactiva y aplicación a muestras reales. Se ha desarrollado un sensor basado en medidas de reflectancia para la determinación de fe(III) y al(III) que utiliza como fase reactiva cromazurol s inmovilizado en distintos soportes. El reactivo pioverdina, sideroforo fluorescente de origen natural que presenta una alta selectividad para el ion férrico, inmovilizado en diversos soportes inertes ha constituido el terminal sensible de dos sensores, caracterizados, tanto en continuo como en fia, para la determinación de hierro. Se ha cuantificado este analito en aguas de distintos orígenes y en suero humano mediante los métodos propuestos

Characterisation of mainstream and passive vapours emitted by selected electronic cigarettes

AbstractElectronic cigarettes have achieved growing popularity since their introduction onto the European market. They are promoted by manufacturers as healthier alternatives to tobacco cigarettes, however debate among scientists and public health experts about their possible impact on health and indoor air quality means further research into the product is required to ensure decisions of policymakers, health care providers and consumers are based on sound science. This study investigated and characterised the impact of ‘vaping’ (using electronic cigarettes) on indoor environments under controlled conditions using a 30m3 emission chamber. The study determined the composition of e-cigarette mainstream vapour in terms of propylene glycol, glycerol, carbonyls and nicotine emissions using a smoking machine with adapted smoking parameters. Two different base recipes for refill liquids, with three different amounts of nicotine each, were tested using two models of e-cigarettes. Refill liquids were analysed on their content of propylene glycol, glycerol, nicotine and qualitatively on their principal flavourings. Possible health effects of e-cigarette use are not discussed in this work. Electronic cigarettes tested in this study proved to be sources for propylene glycol, glycerol, nicotine, carbonyls and aerosol particulates. The extent of exposure differs significantly for active and passive ‘vapers’ (users of electronic cigarettes). Extrapolating from the average amounts of propylene glycol and glycerol condensed on the smoking machine filter pad to the resulting lung-concentration, estimated lung concentrations of 160 and 220mgm−3 for propylene glycol and glycerol were obtained, respectively. Vaping refill liquids with nicotine concentrations of 9mgmL−1 led to vapour condensate nicotine amounts comparable to those of low-nicotine regular cigarettes (0.15–0.2mg). In chamber studies, peak concentrations of 2200μgm−3 for propylene glycol, 136μgm−3 for glycerol and 0.6μgm−3 for nicotine were reached. Carbonyls were not detected above the detection limits in chamber studies. Particles in the size range of 20nm to 300nm constantly increased during vaping activity and reached final peak concentrations of 7×106particlesL−1. Moreover, the tested products showed design flaws such as leakages from the cartridge reservoirs. Possible long term effects of e-cigarettes on health are not yet known. E-cigarettes, the impact of vaping on health and the composition of refill liquids require therefore further research into the product characteristics. The consumers would benefit from harmonised quality and safety improvements of e-cigarettes and refill liquids

Multimethod approach for the detection and characterisation of food-grade synthetic amorphous silica nanoparticles

AbstractSynthetic amorphous silica (SAS) has been used as food additive under the code E551 for decades and the agrifood sector is considered a main exposure vector for humans and environment. However, there is still a lack of detailed methodologies for the determination of SAS’ particle size and concentration. This work presents the detection and characterization of NPs in eleven different food-grade SAS samples, following a reasoned and detailed sequential methodology. Dynamic Light Scattering (DLS), Multiangle Light Scattering (MALS), Asymmetric Flow-Field Flow Fractionation (AF4), Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Transmission Electron Microscopy (TEM) were used. The suitability and limitations, information derived from each type of analytical technique and implications related to current EC Regulation 1169/2011 on the provision of food information to consumers are deeply discussed. In general the z-average, AF4 hydrodynamic diameters and root mean square (rms) radii measured were in good agreement. AF4-ICPMS coupling and pre channel calibration with silica NPs standards allowed the reliable detection of NPs below 100nm for ten of eleven samples (AF4 diameters between 20.6 and 39.8nm) and to quantify the mass concentration in seven different samples (at mgL−1 concentration level). TEM characterisation included the determination of the minimum detectable size and subsequent measurement of the equivalent circle diameter (ECD) of primary particles and small aggregates, which were between 10.3 and 20.3nm. Because of the dynamic size application range is limited by the minimum detectable size, all the techniques in this work can be used only as positive tests

Determination of caesium and its isotopic composition in nuclear samples using isotope dilution-ion chromatography-inductively coupled plasma mass spectrometry

As the natural isotopes of Ba give isobaric interferences on the radioactive isotopes of Cs at nominal masses of 134, 135 and 137, a chemical separation of Cs from Ba has been necessary for the determination of the isotopic composition of Cs by mass spectrometric techniques in highly active nuclear wastes (HAW ), dissolved spent nuclear fuels or radioactively contaminated environmental samples. Ion chromatography (IC ), which allows Cs and Ba to be chemically separated according to their different cationic charge, was coupled to an ICP-MS instrument and the chemical separation was performed on-line and followed directly by mass spectrometry. Three separation schemes were compared with respect to chromatographic resolution, accuracy and precision in irradiated spent fuel samples. The mass discrimination factors for the radioactive Cs isotopes were calculated by using a solution of natural Ba for the different chromatographic processes. They were found to be less than −2.5%. The results obtained by IC-ICP-MS were compared with those obtained by c-spectrometry and with simulation calculations based on the KORIGEN code. The method using a CS5 cation-exchanger column and 1 M HNO 3 as eluent gave a detection limit of 16 pg g−1 for total Cs with a precision of 2.5% at a concentration level of 100 ppb (n=7). Under the same chromatographic conditions, the accuracy of the ratio 134Cs/137Cs, calculated considering the c-spectrometry measurements, was 2.5%. allows the identification of the cooling time of the irradiate

Skin Surface Film Liquid as New Migration Medium for the Determination of PAHs Released from Rubber Containing Consumer Goods

<p>Exposure of consumers, in particular children, to polycyclic aromatic hydrocarbons (PAHs) via contact with consumer products has been the subject of considerable public attention over the last years. Eight PAHs with a harmonized classification as carcinogen 1B, according to the Regulation EC No 1272/2008 on classification, labeling and packaging of substances and mixtures, have been identified in plastic and rubber contained in some consumer articles, such as toys, bicycle grips or sporting goods. These constitute a potential source for dermal, or even oral, exposure. Concerning the former, it is desirable to develop easy and reliable methods for migration determination using simulated environments that mimic as realistically as possible the hydro-lipidic film on human skin composed of aqueous sweat and sebum.</p> <p>This work proposes a protocol for the determination of PAH release from rubber using a migration simulant that mimics real skin conditions. Various compositions of skin surface film liquid (SSFL), a mixture of aqueous sweat and sebum, were tested for their stability and suitability for the measurements. The results indicated that SSFL containing 0.2% sebum showed good agreement with relative migration rates obtained using 20% ethanol, which in past studies has proved to be a valid migration medium for this purpose. The aqueous SSFL has the advantage that it does not interact with the elastomer sample matrix.</p> <p>The SSFL described in this work may serve as a migration simulant for future product-to-skin migration studies, in which the simulant's properties need to realistically reflect the conditions on human skin.</p

Simultaneous Determination of Size and Quantification of Silica Nanoparticles by Asymmetric Flow Field-Flow Fractionation Coupled to ICPMS Using Silica Nanoparticles Standards

This work proposes the use of multimodal mixtures of monodispersed silica nanoparticles (SiO₂–NPs) standards for the simultaneous determination of size and concentration of SiO₂–NPs in aqueous suspensions by asymmetric flow field-flow fractionation (AF4) coupled to inductively coupled plasma mass spectrometry (ICPMS). For such a purpose, suspensions of SiO₂–NPs standards of 20, 40, 60, 80, 100, and 150 nm were characterized by transmission electronic microscopy (TEM), centrifugal liquid sedimentation (CLS), dynamic light scattering (DLS) and by measuring the <i>Z</i>-potential of the particles as well as the exact concentration of NPs by offline ICPMS. An online AF4-ICPMS method which allowed the separation of all the different sized SiO₂–NPs contained in the mixture of standards was developed and the analytical figures of merit were systematically evaluated. The method showed excellent linearity in the studied concentration range (0.1–25 mg L^–1), limits of detection between 0.16 and 0.3 mg L^–1 for smaller and greater particles, respectively, besides a satisfactory accuracy. AF4 calibration with particles with identical nature to those to be analyzed, also permitted accurate size determination in a pragmatic way. Similarly, by using prechannel calibration with NPs for mass determination it was possible to overcome common quantification problems associated with losses of material during the separation and size-dependent effects. The proposed methodology was successfully applied to the characterization in terms of size and concentration of aqueous test samples containing SiO₂–NPs with monomodal size distributions

Determination of the Transport Efficiency in spICP-MS Analysis Using Conventional Sample Introduction Systems : An Interlaboratory Comparison Study

In single particle inductively coupled plasma mass spectrometry (spICP-MS), the transport efficiency is fundamental for the correct determination of both particle number concentration and size. In the present study, transport efficiency was systematically determined on three different days with six carefully characterised gold nanoparticle (AuNP) suspensions and in seven European and US expert laboratories using different ICP-MS instruments and spICP-MS software. Both particle size— (TES)—and particle frequency—(TEF)—methods were applied. The resulting transport efficiencies did not deviate much under ideal conditions. The TEF method however systematically resulted in lower transport efficiencies. The extent of this difference (0–300% rel. difference) depended largely on the choice and storage conditions of the nanoparticle suspensions used for the determination. The TES method is recommended when the principal measurement objective is particle size. If the main aim of the measurement is the determination of the particle number concentration, the TEF approach could be preferred as it might better account for particle losses in the sample introduction system